资源描述：
《分类30圆的有关性质(含解析)》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
30ᙊḄᨵᐵឋ᪆ ஹ⌱⚪1. 2020•⃩T7,3ᑖ/ROḄC,OḄ,CD,AD. NC43=40ᑣNADCḄ ᦪA.110°B.130°C.140°D.160°ூὃM5 ᙊᕜ&'ᳮூ)⚪555*+,-./01,-ூᑖ᪆3C,ᑭᵨᙊᕜ&'ᳮ5ᑮ74cB=90ᑣNB=50ᯠ9ᑭᵨᙊḄᑁ1,-Ḅឋ<=NADCḄ ᦪ.ூ?@?*8C,ABOḄ/.ZACB=90.•.ZB=90o-ZC4B=90°-40o=50°.ZB+ZADC=180P,ZADC=180°-50°=130°.ᦑ⌱*B.ூBC⚪ὃDEᙊᕜ&'ᳮ*ᙠGᙊᡈIᙊJGKᡈIKᡠMḄᙊᕜ&NIOIPQᩩKᡠMḄᙊS&Ḅ T.TᙊᡈᡠMḄᙊᕜ&&90Ḅᙊᕜ&ᡠMḄU.2. 2020•1VᑁW,T8,3ᑖAஹBஹCஹᙠZ4OC=120°,8AC
1ḄJᑣ/Ḅ ᦪ40°C.50°D.60'ூὃM4*ᙊS&ஹKஹUḄᐵZ[M5*ᙊᕜ&'ᳮ[M6ᙊᑁ1,-Ḅឋ<ூ)⚪64*\]^;559*ᙊḄᨵᐵᭆbcឋ<ூᑖ᪆03,ᑭᵨᙊS&ஹKஹUḄᐵZ5ᑮZAOB=NCO3=LN4OC=60,2ᯠ9᪷eᙊᕜ&'ᳮ5ᑮNOḄ ᦪ.ூ?@?*08,,8ACḄJZAOB=ZCOB=-ZAOC=-xl20°=60°,22ZD=-^AOB=30°.2ூBC⚪ὃDEᙊᕜ&'ᳮ*ᙠGᙊᡈIᙊJGKᡈIKᡠMḄᙊᕜ&NIOIPQᩩKᡠMḄᙊS&Ḅ T.3. 2020fgWᱝiWT14,3ᑖ1,-AfiCDᑁPj. QNBDC=50°,ᑣZADCḄ ᦪOD
2A.125°B.130°C.135°D.140°ூὃM4*ᙊS&ஹKஹUḄᐵZ[M5ᙊᕜ&'ᳮ[M6*ᙊᑁ1,-Ḅឋ<ூ)⚪14*lm⚪[64*\]^ூᑖ᪆04,OB,OC,᪷eᙊᕜ&'ᳮ5nN80C=100o᪷e4C=BC5ᑮZAOC,pq5ᑮNABC,ᨬ9ᑭᵨᙊᑁ1,-Ḅឋ<5ᑮst.ூ?@?*Q4,OB,OC,NBDC=50,ZBOC=2ZBDC=100°,AC=BC,.-.ZBOC=ZAOC=100o,ZABC=-ZAOC=50°,2s.ZADC=1800-ZABC=130°.ூBC⚪ὃDEᙊᕜ&'ᳮKஹUஹᙊS&ḄᐵZᙊᑁ1,-Ḅឋ<ᐵuᙠPvnT᪀⌼ᙊS&.4.2020yᓅ{|T10,3ᑖE,F,GᙊḄ}NEEG=50~ᙊSḄ
35,O'C.U------XGD.pூὃM5*ᙊᕜ&'ᳮூ)⚪559*ᙊḄᨵᐵᭆbcឋ<ூᑖ᪆ᑭᵨᙊᕜ&'ᳮMᔜ⌱⚗0ᑨ.ூ?@?*ZFEG=50P, PᙊS4FPG=24FEG=100°.ᦑ⌱*C.ூBC⚪ὃDEᙊᕜ&'ᳮ*ᙠGᙊᡈIᙊJGKᡈIKᡠMḄᙊᕜ&NIOIPQᩩKᡠMḄᙊS&Ḅ T.5. 2020•ḝT8,4ᑖ1,-ḄᙊO,BC=CD,N/MC=35ZACD=45°.ᑣNAZJBḄ ᦪூὃM4 ᙊS&ஹKஹUḄᐵZூ)⚪64*\]^[559*ᙊḄᨵᐵᭆbcឋ<ூᑖ᪆ᑭᵨᙊS&ஹKஹUḄᐵZ5ᑮOC=BC,oᑭᵨᙊᕜ&'ᳮ5ᑮZfi4C=ZZMC=35°,ZABD=ZACD^=45°,ᯠ9᪷e}&-ᑁ&/4D5Ḅ ᦪ.ூ?@?*BC=CD,DC=BC,:.ZBAC=ZDAC=35°,ZABD=ZACD=45°,
4/.ZADB=180°-Zfi4Z5-ZABZ)=180°-70°-45°=65°.ᦑ⌱*C.ூBC⚪ὃDEᙊS&ஹKஹUḄᐵZ*ᙠGᙊIᙊJNIḄᙊS&ᡠMḄKNI,ᡠMḄUNI.ᙠGᙊᡈIᙊJtᙊS&ஹᩩKஹᩩUJᨵ NI¡¢£ᡠM¤Ḅᐸ¦ᔜOᑖ§NI.6.2020yᓅ©ªT9,3ᑖᙠT3ḄJACUDACḄJACBDஹE. E°>ḄJᑣACḄ²A.-^3B.36C.3>/2D.4722ூὃM2*ᚖ'ᳮ[M4*ᙊS&ஹKஹUḄᐵZூ)⚪67*µᳮ¶*559*ᙊḄᨵᐵᭆbcឋ<ூᑖ᪆OD,ACF,᪷eᚖ'ᳮ5nOD^AC,AF=CF,ql5DF=BC,᪷e}&-J·¸'ᳮ=50¹=L8=0/BC=DF=2,ᑭᵨ»¼'ᳮᓽ~22=5AC.ூ?@?*OD,¿ACP¹DACḄJ:.ODLAC,AF=CF,.\ZDFE=90°OA=OB,AF=CF,. .OF=-BC.2AB.•.ZACS=90ᙠAEFDAECBJ
5Z£>FE=ZACB=90°
6ூ)⚪559*ᙊḄᨵᐵᭆbcឋ<[67*µᳮ¶.ூᑖ᪆Ó8CD,᪷e»¼'ᳮ=n3D,᪷eᙊᕜ&'ᳮ5ᑮNBAC=/BOC,᪷e¦UḄ'Ô?@ᓽ~.ூ?@?*ÓBCD,ᵫ»¼'ᳮ5"+4?=29,CD42^/5ᙠRt^BQCJcosZBDC=——=—BD25ᵫᙊᕜ&'ᳮ5NBAC=/BDC,275cosZBAC—cosZBDC-----,5ᦑ⌱*B.ூBC⚪ὃDḄ}&-Ḅᙊ.SÅÆᙊᕜ&'ᳮஹ¦UḄ'Ô?⚪Ḅᐵu.8. 2020•Ö×ØᙥT9,3ᑖÚÛÜÝÉÞḄA./01,-ḄM,NIB.ᙊᕜ&IPᙊS&Ḅ TC.ᑖßÊà—L=3—2Ḅ?x=2x—2x—2D.}&-Ḅ &IPᑁ&ḄூὃB2ᑖßÊàḄ?[M5ᙊᕜ&'ᳮ*L5/01,-Ḅឋ<[M4ᙊS&ஹKஹUḄᐵZூ)⚪522*ᑖßÊàc¤ᵨ[559*ᙊḄᨵᐵᭆbcឋ<[555*+,-./01,-[69*¤ᵨâãூᑖ᪆᪷e/01,-Ḅឋ7Êàᨵäå~MC0ᑨ[᪷e}&-&ឋ8/.ZBOC=60°,DM=CM,S&OBC=S&OBDOC/1DB,q—q4&OBD-•*,S&OBC=SA05c'J▢óôᑖḄ☢ö=6 M 2ü=2ý,360ூBC⚪ὃDEᚖ'ᳮஹᡧ-☢öḄᙊᕜ&'ᳮþÿ ᑮᐵḄ ⚪Ḅᐵ.10. 2020•T14,3ᑖ ᙠ!A3"#N4OC=80.$"%ACḄ!$$E"BC&'()$.ᑣNCaḄᜧ,-./ூὃ$M5 ᙊᕜ5ᳮ7M48ᙊ9ஹ;ஹ%Ḅᐵ<ூ=⚪5588>?ஹ@ABCD75548EῪBூᑖ᪆HI8ஹOE,KN8OE=x,ᑣNCOE=l Xo-x,ZDOE=100°-x+40°,᪷MEῪḄឋOPᑁP5ᳮRSZDEO^Z.CEO,ᓽ-RSᫀ.
9ூ 8HI8ஹOE,OC=OA,4cEῪ$"%Ḅ!$:.ZDOC=40°,ZBOC=100°,KZBOE=x,!JliJZCOE=100o-x,ZDOE=1000-x+40°,OC=OE,ZCO£'=100°-x,ZOEC=ZOCE=400+L,2OD(40°+x)-(20°+!x)=20°,ZCED<40°ᦑ⌱8C.ூ$w⚪ὃxyᙊ9ஹ;ஹ%z{Ḅᐵ<ᙊᕜ5ᳮEῪḄឋOE|}$,.RSNOECPNOEZḄᦪ ⚪Ḅᐵ.11./2020•☘T6,3ᑖ 8Ḅ#$A,Cᙠ&=ADAC8$G.NCO£>=126ᑣ/AG8Ḅᦪ"/)C.110°D.117°ூὃ$M48ᙊ9ஹ;ஹ%Ḅᐵ<7M58ᙊᕜ5ᳮ.ூ=⚪5598ᙊḄᨵᐵᭆឋO7648.
10ூᑖ᪆᪷Mᙊᕜ5ᳮᑮNBAO=90ZDAC=ZCOD=63°,ᵫAg=A£ᑮ/B=/O=45ᯠ᪷MឋO/AG8Ḅᦪ.ூ 88BḄ#AZBAD=90%"&'ABAD> .NB=ND=45,11ZDAC=-ZCOD=-xl26°=63°,22ZAGB=ZDAC+Z£>=63°+45°=108°.ᦑ⌱8B.ூ$w⚪ὃxyᙊᕜ5ᳮ8ᙠᙊᡈEᙊ!;ᡈE;ᡠCḄᙊᕜEEᩩ;ᡠCḄᙊ9Ḅ)¢.£¤8¢ᙊ/ᡈ#ᡠCḄᙊᕜ90ḄᙊᕜᡠCḄ%#.12. 2020•¥¦,T1,3ᑖ ABḄ%$Cᙠ§$5Ḅᑗ&OCLOA,OCA5$©.N8PC=70ᑣNA8CḄᦪE/A.75°B.70°C.65°D.60°ூὃ$M2 ᚖ#5ᳮ7MC-.ᑗḄឋO7A/58ᙊᕜ5ᳮூ=⚪55A8BᙊᨵᐵḄ«¬ᐵ<7648ூᑖ᪆ᐜᑭᵨC⚔EP±²ᑮNA=20ᑭᵨEῪḄឋOᑮZOBA=ZA=20°,ᯠ᪷MᑗḄឋOᑮOB_LBC,³´ᑭᵨ±²SZ4BCḄᦪ.ூ 8OC_LOA,/.ZAOC=90°,ZAPO=ZBPC=JO0,
11.•.ZA=90°-70°=20°,OA=OB,.•.ZOBA=ZA=20°,BCOḄᑗ.-.OBA.BC,.•.Z<9BC=90°,/.ZABC=90°-20°=70°.ᦑ⌱8B.ூ$w⚪ὃxyᑗḄឋO8ᙊḄᑗᚖµ§ᑗ$Ḅ¢#7S¶ᙊḄᑗ·H§ᑗ$Ḅ¢#᪀⌼5ᳮ Sᚖᐵ<.1. 2020•ᒹᜮ T9 3ᑖ ABOOḄ#C%$C,¼ᙠ#ABḄ½¾.ZAOCZAODNDOB=27811,CD=4,ᑣCOḄ"/A.2nB.4nC.-------D.s/2TT2ூὃ$MN8;Ḅ.ூ=⚪5548EῪB755C8BᙊᨵᐵḄ7668¿.¼.ூᑖ᪆᪷M>5ÀPÁ|RSZAOD=70°,/8=110°,ZCOA=20°,RSNCOQ=90°, RS¢#0£>,᪷M;ÂÃRSᓽ-.ூ 8VZAOCAAOD-.NDOB=27811,40+/8=180°,77./AOO=--------X180°=70°,NDOB=110°,/COA=20°,7+11AZCOD=ZCOA+ZAOD^90°,'OD=OC,CD=4,
12.\2OD2=42, .OD=2y/2,...„90/r+2A/2n-CDḄ----------=ᐔ,180ᦑ⌱8D.ூ$w⚪ὃxy P;ÂÃ.RS¢#0Ḅ ⚪Ḅᐵ.1./2020ÇᓭÉÊËT5,3ᑖ ÌÍÎ8"ḄᑁIÌÍÁ|N8CZ"120ᑣN88Ḅᦪ"/A.100°B.110°C.120°D.130°ூὃ$M5 ᙊᕜ5ᳮ7M48ᙊ9ஹ;ஹ%Ḅᐵ<ூ=⚪5598ᙊḄᨵᐵᭆឋO7678£ᳮ.¼ூᑖ᪆᪷MᙊᑁIÌÍḄឋORSNA᪷Mᙊᕜ5ᳮᑮᫀ.ூ 8ÌÍABCDOḄᑁIÌÍ/.Z4=180°-ABCD=60°,ᵫᙊᕜ5ᳮZBOD=2ZA=120°,ᦑ⌱8C.ூ$w⚪ὃxḄᙊᑁIÌÍḄឋOÏÐᙊᑁIÌÍḄC±⊡ ⚪Ḅᐵ.2.1./3ᑖ/2020•⃩Ó 49"OḄ#$C,$&Ḅ½$HIC4,CD,AD.NC4B=40ᑣ/ADCḄᦪ/DB
13A.110°B.130°C.140°D.160°ூὃ$M5 ᙊᕜ5ᳮூ=⚪5558ÔÍB>ÕÌÍூᑖ᪆HI3C, ᑭᵨᙊᕜ5ᳮᑮNACB=90ᑣNB=50ᯠᑭᵨᙊḄᑁIÌÍḄឋORNAOCḄᦪ.ூ 8 HIBC,ABḄ#/.ZACB=90°,NB=90°-NC4B=90°-40°=50°,ZB+ZADC=180/.ZADC=180°-50°=130°.ᦑ⌱8B.ூ$w⚪ὃxyᙊᕜ5ᳮ8ᙠᙊᡈEᙊ!;ᡈE;ᡠCḄᙊᕜEEᩩ;ᡠCḄᙊ9Ḅ)¢.¢ᙊ/ᡈ#ᡠCḄᙊᕜ90ḄᙊᕜᡠCḄ%#.3.1. 2020ÇᓭÖ¦T7,4ᑖ Á|P4,PBOḄ½ᩩᑗA,Bᑗ,OP$M.×SØᑡÌÚÛÜ8জPA=PB.@OPLAB.ঞÌÍOAP8ᨵIᙊ7টMAAOPIᙊḄᙊ9.ᐸ!àáÛÜḄâᦪ/
14AA.1B.2C.3D.4ூὃ$MC ᑗḄឋO7MA ḄIᙊB9ூ=⚪308ᙊḄᨵᐵᭆឋO318$BᙊḄ«¬ᐵ<;ூᑖ᪆ᑭᵨᑗ5ᳮCজåÕᑨç;ᑭᵨḄᚖ>ᑖ5ᳮḄ⌮5ᳮCঝåÕᑨç;ᑭᵨᑗḄឋOPᙊᕜ5ᳮ-CঞåÕᑨç7ᵫêᨵëNAPO=30ìOP=2OA,ì©í=OM,ᑣ-CটåÕᑨç.ூ 8PA,PBOḄ½ᩩᑗA,Bᑗஹ,:.PA=PB,ᡠîজàá;OA=OB,PA=PB,.•.OPᚖ>ᑖ4?,ᡠîঝàá;PA,P8OḄ½ᩩᑗA,8"ᑗ$,:.OAVPA,OBLPB,:.ZOAP=ZOBP=9Q°,.•.$Aஹ3ᙠîOP"#Ḅᙊ&,.•.ÌÍ4P8ᨵIᙊᡠîঞàá;êᨵëNAPO=30ìOP=2OA,MPM=OM,ï)5"AAOPIᙊḄᙊ9ᡠîট┯ñ.ூ$w⚪ὃxyᑗḄឋO8ᙊḄᑗᚖµ§ᑗ$Ḅ¢#.S¶ᙊḄᑗ·H§ᑗ$Ḅ¢#᪀⌼5ᳮ Sᚖᐵ<.òὃxyᑗ5ᳮ.
152. 2020ᔡ᧡T6,3ᑖ 4?OḄ#$CஹᙠO±,ZBDC=20°.ᑣNAOCḄᜧ,"/A.400B.1400C.160°D.170°ூὃ$M48ᙊ9ஹ;ஹ%Ḅᐵ<7M58ᙊᕜ5ᳮூ=⚪308ᙊḄᨵᐵឋO7648ூᑖ᪆ᐜᑭᵨᙊᕜ5ᳮᑮNBOC=40ᯠ᪷Mö⊡Ḅ5ÀSZ4OCḄᦪ.ூ 8ZBOC=2ZBDC=2x20°=40°,/.ZAOC=180°-40°=140°.ᦑ⌱8B.ூ$w⚪ὃxyᙊᕜ5ᳮ8ᙠᙊᡈEᙊ!;ᡈE;ᡠCḄᙊᕜEEᩩ;ᡠCḄᙊ9Ḅ)¢.4.1. 2020•ᵞᾓùúT9,3ᑖ AO&)$8C#AC=2,/ᵫ=4,A.2ûB.75C.20D.x/10ூὃ$M5 ᙊᕜ5ᳮூ=⚪5598ᙊḄᨵᐵᭆឋO75548EῪB7698üᵨ(}ூᑖ᪆ᐜ᪷Mᙊᕜ8ZBAC=ZD=900,᪷Mýþ5ᳮᓽ-ÿ .ூ:ᙠOᑖ8C,BD=CD,
16BCOḄ.•.ZBAC=ZD=90°,AC=2,AB=4,BC=6+42=25,RtABDCDC2+BD2=BC2,2DC2=20,DC=M,ᦑ⌱D.ூ⚪ὃᙊᕜ ᳮ!" ᳮ#$%⚪Ḅᐵ'(ᮣ*+ᵨᡠ.$%/0⚪,.2ᑭᵨ!" ᳮ456Ḅ789ὃ:ὃ⚪;.1. 2020ᵞᾓ>?ஹABT9,3ᑖCEA(FBC(AC=2,AB=4,A.2>/2B.C.275D.V10ூὃM5ᙊᕜ ᳮூG⚪559ᙊḄᨵᐵᭆJKឋMN554#ῪP QR P QN69SᵨT%ூᑖ᪆ᐜ᪷Xᙊᕜ YNS4c=/=90᪷X!" ᳮᓽ]Y^ .ூᙠᑖBC,BD=CD,BCOḄZBAC=ZD=90°,AC=2,AB=4,BC=V22+42=2A/5,RtABDCDC2+BD2=BC2,
1720c2=20,DC=M,ᦑ⌱D.ூ⚪ὃᙊᕜ ᳮ!" ᳮ#$%⚪Ḅᐵ'(ᮣ*+ᵨᡠ.$%/0⚪,.2ᑭᵨ!" ᳮ456Ḅ789ὃ:ὃ⚪;.2.b2020cdef,T4,4ᑖCE(OḄᑗ5AlᑗmnQ4,.p48=35,ᑣNAO8ḄvᦪlbCூὃMC ᑗ5ḄឋMூG⚪55ARᙊᨵᐵḄxyᐵz67}ᳮ~ூᑖ᪆᪷Xᑗ5ḄឋMYᑮ/3=90᪷X P QḄ┦ ᓽ].ூ(Ḅᑗ5:.OA±AB,.-.ZOAB=90°,ZAOB=90FNB=55°,ᦑ⌱B.ூ⚪ὃḄ(ᑗ5ḄឋMᙊḄᑗ5ᚖ9ᑗḄ(⚪Ḅᐵ'.5.1.b2020T7,4ᑖCEQ48cḄ⚔A,B,CᙠO8OḄᑗ54Ḅ759.pḄl1,ᑣḄ7lbCA.1B.2C.72D.GூὃL8QḄឋMNMC-.ᑗ5ḄឋMNM5ᙊᕜ ᳮ
18ூG⚪55ARᙊᨵᐵḄxyᐵzN67}ᳮ~ூᑖ᪆mn08,᪷XQḄឋMYᑮ4=9,4Y4403=60᪷Xᑗ5ḄឋMYᑮN£C8O=9bP, P Qᓽ]Yᑮ^ .ூmn03,cQQ4BC(Q/.OA=ABOA=OB,OA=AB=OB:.ZAOB=60P,BDOḄᑗ5:.ZDBO=90°,OB=\,:.BD=>/3OB=y/3,ூ⚪ὃᑗ5ḄឋMQḄឋM#P QḄᑨ ¢ឋM P Q,£¤¥¦ᑗ5ḄឋM ᳮ(⚪Ḅᐵ'.1.b2020•¨©T6.4ᑖCER4(OḄᑗ5AlᑗOP9B,ZP=10,CᙠOCV/A8.ᑣN84C#9bC
19B“ஹO)A.20°B.25°C.30°D.50°ூὃM5 ᙊᕜ ᳮNMC ᑗ5ḄឋMூG⚪55ARᙊᨵᐵḄxyᐵzN67}ᳮ~ூᑖ᪆mn4,᪷Xᑗ5ḄឋMYᑮNQ4O=904®NAOP,᪷X#ῪP QḄឋMஹ¯5ḄឋM4®NBOC,᪷Xᙊᕜ ᳮᓽ].ூmn4,(Ḅᑗ5:.OA±AP,ZPAO=90°, •.ZAOP=90°-ZP=80°,OA=OB,.\ZOAB=ZOBA=50°,OCI/AB,ZBOC=ZOBA=50°fᵫᙊᕜ ᳮYZBAC=-ZBOC=25°,2ᦑ⌱B.
20Bூ⚪ὃḄ(ᑗ5ḄឋMஹᙊᕜ ᳮஹ¯5ḄឋMஹ#ῪP QḄឋMᙊḄᑗ5ᚖ9ᑗḄ(⚪Ḅᐵ'.2. 2020•¨©T8.4ᑖCEAABC(ḄᑁnP QAB=BC,ZE4c=30AD(4=8,ᑣACḄ7lbCOA.4B.46C.-A/3D.2733ூὃMAP QḄnᙊR³N´4ᙊ³ ஹµஹ¶ḄᐵzNM5ᙊᕜ ᳮூG⚪559ᙊḄᨵᐵᭆJKឋMN67}ᳮ~ூᑖ᪆mn8,᪷X#ῪP QḄឋMYᑮNACB=N5AC=30᪷XᙊᑁncQḄឋMYᑮ"=180-28=604YNC40=3O᪷X P QḄឋMᓽ]Yᑮ^ .ூmnCD,AB=BC,ZZMC=30°,/.ZACB=ZBAC=30°,/.ZB=180°-30°-30°=120°,/.ZD=180o-ZB=60°,.-.ZC4£>=30°,
21A£(/.ZACD=90°,AD=8,.-.CD=-AD=4,2AC=yjAD2-CD2=Jg-G=4^,ᦑ⌱B.ூ⚪ὃP QḄnᙊR³ᙊᕜ ᳮ¸30 Ḅ P QḄឋM,!" ᳮ¥¦Ḅ%¹EQ(⚪Ḅᐵ'.3. 2020•º»T8.3ᑖC¼ ᘤ¾ v¿ÁḄxyEᡠÂᙠAAOBÃ5OCABD,ᑣNADCḄvᦪlbCA.60°B.70°C.80°D.85°ூὃM5ᙊᕜ ᳮூG⚪66+~N559ᙊḄᨵᐵᭆJKឋMூᑖ᪆᪷X#ῪP QḄឋMP QḄ ḄឋMᓽ]Yᑮ^ .ூOA=OB,ZAOB=140°,ZA=ZB=g 180°-140°=20°,ZAOC=60°,/.ZADC=ZA+ZAOC=200+60°=80°,
22ᦑ⌱c.ூ⚪ὃᙊᕜ ᳮ#ῪP QḄឋMP Q ḄឋM¥¦Ḅ%¹EQ(⚪Ḅᐵ'.1. 2020▷ÅT9,3ᑖCEAABCᑁn9ZA=50°.E(8cḄmnOEÆ79mnBQ,ᑣ/ḄᜧÈlbCA.55°B.65°C.60°D.75°ூὃM5ᙊᕜ ᳮNMAP QḄnᙊR³.ூG⚪559ᙊḄᨵᐵᭆJKឋMN67}ᳮ~.ூᑖ᪆mnC᪷XᙊᑁncQḄឋMYᑮNCZ8=180-N4=130᪷Xᚖ ᳮYᑮOO_L8C,BD=CD,᪷X#ῪP QḄឋMᓽ]Yᑮ^ .ூmnCD,,/ZA=50°,AZCDS=1800-NA=130°,(BCḄODA.BC, .BD=CD, .ZODB=ZODC=-NBDC=65,ூ⚪ὃP QḄnᙊR³ᙊᑁncQḄឋMᚖ ᳮ#ῪP QḄឋM¥¦Ḅᳮ⚪T(⚪Ḅᐵ'.
231. 2020ÉT7,3ᑖCEAB=AC,NABC=70.ᑣNBOCḄvᦪlbCA.100°B.90°C.80°D.70°ூὃM5ᙊᕜ ᳮNM4ᙊ³ ஹµஹ¶ḄᐵzூG⚪64ÊËÌN559ᙊḄᨵᐵᭆJKឋMூᑖ᪆ᐜ᪷Xᙊᕜ ᳮYᑮNA8C=N4C8=70ÍᑭᵨP Qᑁ ¢®ZA=40°,ᯠÏ᪷Xᙊᕜ ᳮYᑮNBOCḄvᦪ.ூAB=AC,...ZABCÐ=70°,.'.ZA=180°-70°-70°=40°,.-.ZBOC=2ZA=80°.ᦑ⌱C.ூ⚪ὃᙊᕜ ᳮᙠÑᙊᡈ#ᙊѵᡈ#µᡠÓḄᙊᕜ Ô#Õ#9ÖᩩµᡠÓḄᙊ³ ḄF.6.1. 2020ᓅÙT4,2ᑖCÚᑡEQÜ(³ÓÝEQÞ(ßÓÝEQḄ(bCூὃP3ßÓÝEQNR5 ³ÓÝEQூG⚪558àஹáâRÓÝN64ÊËÌூᑖ᪆᪷XßÓÝEQR³ÓÝEQḄᭆJ4.
24ூAஹÜã(ßÓÝEQÞã(³ÓÝEQᦑä⌱⚗ãᔠ⚪TN8ஹÜã(ßÓÝEQÞã(³ÓÝEQᦑä⌱⚗ãᔠ⚪TNCஹã(ßÓÝEQ(³ÓÝEQãᔠ⚪TNஹÜ(³ÓÝEQç(ßÓÝEQèᔠ⚪T.ᦑ⌱D.ூ⚪ὃ³ÓÝEQ¢ßÓÝEQḄ$%ᐵ'(é³ÓÝEQRßÓÝEQḄᭆJ.ßÓÝEQḄᐵ'(êëÓÝßEQìᑖᢚîÏ]eᔠ³ÓÝEQ(⌕êëÓݳEQáâ180ÏRðEeᔠ.2.b2020ñòT4,4ᑖCÚᑡó®Ḅ#P Qஹ¯cQஹᙊKᡧQÜ(ßÓÝEQç(³ÓÝEQḄ(bCூὃR5 ³ÓÝEQNP3 ßÓÝEQூG⚪55Fᢗ÷RøEN64ÊËÌூᑖ᪆᪷XßÓÝEQR³ÓÝEQḄᭆJ4.ூA.#P Q(ßÓÝEQã(³ÓÝEQNB.¯cQã(ßÓÝEQ(³ÓÝEQNC.ᙊÜ(ßÓÝEQç(³ÓÝEQND.ᡧQ(ßÓÝEQã(³ÓÝEQ.ᦑ⌱C.ூä⚪ù⌕ὃ³ÓÝEQRßÓÝEQḄᭆJ.ßÓÝEQḄᐵ'(êëÓÝßEQìᑖᢚîÏ]eᔠ³ÓÝEQ(⌕êëÓݳáâ180vÏìᑖeᔠ.7.1.b2020©úT9,4ᑖCû$A,B,CᙠᑣÚᑡü⚪lýü⚪Ḅ(bA.p08ᑖ¶AC,ᑣcQQ48C(¯cQ
25B.pcQABC(¯cQᑣ=120C.pNABC=120ᑣ¶ACᑖ08D.p¶ACᑖ08,ᑣ08ᑖ¶ACூὃO1ü⚪R ᳮூG⚪67}ᳮ~N559ᙊḄᨵᐵᭆJKឋMூᑖ᪆᪷Xᚖ ᳮ¯cQḄឋMᑨþᓽ].ூAஹEBpOBᑖ¶AC,ᑣcQABCãF (¯cQNðü⚪(Ꮇ ⚪;BஹQ4BCᑣAB=OC,OA=BC,OA=OB=OC,:.AB=OA=OB=BC=OC,..ZABO=NO3C=60°,:.ZABC=120°, ⚪;NABC=120ᑣACᑖOB, ⚪Ꮇ ⚪;DஹACᑖ08,ᑣ08ᑖAC, ⚪Ꮇ ⚪;
26ᦑ⌱ B.ூ !⚪ὃ#Ḅ ⚪ḄᎷᑨ&'(Ḅ ⚪) ⚪┯+Ḅ ⚪),Ꮇ ⚪.ᑨ& ⚪ḄᎷᐵ/⌕1៉3!4Ḅឋ6ᳮ.1. 202089:;T4,3ᑖ<=>438ᑁ@AO,ZABC=1O°,ᑣN/CCḄBᦪD27AB=48,:.BD=-AB=-x48=24,22Ḅcd52,,-.OH=OC=26,ᙠRtAOBD4OD=JOB2-BD?=126?-24,=10,CD=OC-OD=26-10=16(CTO),ூ !⚪ὃ#]ᚖᳮஹᳮ{>H᪷T⚪᪀⌼cG}G[\⚪Ḅᐵ/.2. 2020ᵞᾓT9,3ᑖ<A 8CcAC=2,AB=4,A.2yB.C.2D.Mூὃ M5 ᙊᕜGᳮூI⚪559 ᙊḄᨵᐵᭆLMឋ6H554 {Ὺ}G~cG}GH69 yᵨூᑖ᪆ᐜ᪷TᙊᕜGW N8AC=ZD=90᪷TᳮᓽVWYZ.ூ[\[ ᙠᑖBC,BD=CD,BCOḄc,
28:.ZBAC=ZD=90°,AC=2,AB=4,BC=72?+4?=2⍩,RtABDC4DC2+BD1=BC2,20c2=20,DC=y/10,ᦑ⌱ D.ூ !⚪ὃ#ᙊᕜGᳮᳮ{>[⚪Ḅᐵ/ᮣ£Nᵨᡠ¤>[¥¦⚪,¤§ᑭᵨᳮ©ḄªA4ὃ«ὃ⚪¬.2. 202089T8,3ᑖ<O{AABCḄᑁᑗᙊᑖ¯ᑗ43,BC,ACA E,F,D,PF ᑣNEP°ḄBᦪD29NEPF=-NEOF=60°,2ᦑ⌱ B.ூ !⚪ὃ#}GḄᑁᑗᙊ~ᑁ±ᑗḄឋ6ᙊᕜGᳮ{>[⚪Ḅᐵ/1^_`´!>ªA4ὃ«ὃ⚪¬.3. 202089µ;T9,3ᑖ<=>3cḄc041. ᙠ¶·ACD~ A, C¸ᔠ=a,ZAOD=J3,ᑣD30ᑡÏÐ জm Adᙊ±〉ÔḄBd·ᑖ¯AB,ACA E,F,ᑖ¯m E,ᔆdᙊ±ᜧAØᡠḄd·ÙA H,Û2ঝᑖ¯m A,8dᙊ±ᜧAÞ48Ḅd·ÙA N,cMN,2ÛA OHঞm dᙊ±©4dᙊ.ூὃ N3 -äᩖHM2 ᚖᳮHKH-.{Ὺ}GḄឋ6ூI⚪13 ⚪H69 yᵨூᑖ᪆ºOAAT.[cG}GAT,ᙠRtAOCT4ᑭᵨᳮ᪀ìíîᓽV[¥¦⚪.AOA.BC,BT=TC=4,AT=y/AC2-CT2=J(2>/5)2-42=2,
31ᙠRtAOCT4ᑣᨵ=(r-2)?+42,[W/'=5,ᦑ⌱ D.ூ !⚪ὃ#-äᩖ{Ὺ}GḄឋ6ᚖᳮ{>[⚪Ḅᐵ/ᳮ[⚪ᮣ£Nᵨᡠ¤>[¥¦⚪.2. 2020öìT9,4ᑖ<A88ᑁ@AO,AB=CD,Ad34 ZBDC=60°,ᑣ/AD8{AD32A5øḄᙊᕜGḄBᦪ*80=402ᦑ⌱ A.ூ !⚪ὃ#]ᙊᕜGᳮᙊ±Gஹ·ஹüýḄᐵÁ{> P᪷TᳮAB=AD=CD[⚪Ḅᐵ/.1. 2020:ᓭÿ T9,3ᑖ20203ᨴ14 “▭ᦪ”.⁚Ḅ᧫“ᐔDay▭ᦪᡠ ᙠ3ᨴ14 “3.14”!ᙊᕜ᳛ᦪ%ᨬ'(Ḅᦪ).ᙠ*+ ,ᡠ-.Ḅᙊᕜ᳛Ḅ/012 3 4⊝6,78ᦪ!9ᢈ;<=>Ḅ?⌕᪗B.ᡃᓭᓅF8ḄἔHIJKᨬLMᙊᕜ᳛Ḅ/0%N-ᑮPᦪQR7SḄ9Tᓈ VᡂX⚞ᐜIJᓟ\. ]^_ᙊᕜ᳛Ḅ`⊤bcজᙊᕜ᳛ᨵᳮᦪgঝᙊᕜ᳛iᳮᦪcঞᙊᕜ᳛!ᙊḄᜧPiᐵḄmᦪ no_VᙊḄᕜp!qrḄsgটᙊᕜ᳛!ᙊḄᜧPᨵᐵḄmᦪ no_VᙊḄᕜp!urḄs.ᐸw⊤bx0ḄyzA.ঝঞB.জঞC.জটD.ঝটூὃQ1Hc(ᦪᨵᦔᦪ)g27cᦪ.ூ⚪511cᦪg67cᳮ.ூᑖ᪆᪷ᦪḄᑖᐔḄᱯQᓽ3.ᫀ.ூc ᙊᕜ᳛iᳮᦪ !ᙊḄᜧPiᐵḄmᦪ no_VᙊḄᕜp!qrḄs ᡠ ⊤bx0Ḅyzঝঞgᦑ⌱cA.ூQ⚪ὃᦪ ᦪḄᑖ“ᐔ”Ḅ⚪Ḅᐵ.1. 2020•ₚ¢ T7•3ᑖ¤ 0w OCLAB,ZAPC=28°,ᑣN8OCḄ2ᦪ
33C.42°D.56°ூὃQM4cᙊ®¯ஹ±ஹ²Ḅᐵ³gM2cᚖr ᳮgM5cᙊᕜ¯ ᳮூ⚪559cᙊḄᨵᐵᭆ·¸ឋºூᑖ᪆᪷ᚖr ᳮ 3.»¼½ ZAPC=28%᪷ᙊᕜ¯ ᳮ 3.NBOC.ூcᙠw OC.LAB,AC=BC,NAPC=28 /.ZBOC=2ZAPC=56°,ᦑ⌱cD.ூQÈ⚪ὃᙊᕜ¯ ᳮ ᑭᵨᚖr ᳮ.»=Ë⚪ᐵ.2.2020ÍᓭÎÏ T9,4ᑖ¤ᡠÑ Q4ஹBஹC^ÒḄÓ2ᑖÔ0ஹ2ஹ4ஹÕÖ×C4ØQCᢥÚ8┐ÜᔣÞß 7QA✌áâᙠãä3CDEḄç2EK8 èQAi,ᑣ8Ö×CAêëḄ¤äḄ☢íூὃQLBcãäḄឋºgMOcᡧä☢íḄN-gR2cÞßḄឋº.ூ⚪559cᙊḄᨵᐵᭆ·¸ឋºg66cò-.ூᑖ᪆óÖ×CAêëḄ¤äḄ☢í ᓽóᡧä4c41Ḅ☢í.
34ூcᵫ⚪ ÷AC=4,BC=4-2=2,ZAiBC=90°.ᵫÞßḄឋº .AiC=AC=4.1,BC1ᙠRs4BCw cos/4cAi=------=—.A,C2ZACAi=60°.ᡧäAC4Ḅ☢íᜐK¼=»7.3603QᓽÖ×CAêëḄ¤äḄ☢í2ú.3ᦑ⌱cD.ூQ⚪ὃᡧä☢íḄN-q¯û¯ä ᡧä☢íüýÈ⚪Ḅᐵ3. 2020þÿ T7,2ᑖḄCḄCAஹ3ᔠCHLAB,ᚖM8CḄ. OḄ 3,ᑣ!Ḅᨬᜧ$A.3B.4C.5D.6ூὃKP()*)+,-Ḅ.ூ/⚪55412Ὺ*)+()*)+46715ᳮ78ூᑖ᪆᪷;()*)+,-.Ḅឋ=>?( ᙊᨬᜧḄᓽBCDḄᨬᜧ$3ூEFE1CH_LAB,ᚖ.".ZCMB=90°.8cḄ.2BCḄᨬᜧ$( Ḅ!OḄ 3,
35r.MWḄᨬᜧ$3,ᦑ⌱1A.ூJK⚪ὃLM()*)+,-(.Ḅឋ=NO8cḄᨬᜧ$Ḅ( Ḅ!E⚪ḄᐵQ.4. 2020RSTUT7,3ᑖAஹBஹCᙠZACB=54°,ᑣNA6OḄWᦪA.54°B.27°C.36°D.108°ூὃ1ᙊY)ஹஹḄᐵZ1M51ᙊᕜ)\ᳮூ/⚪55412Ὺ*)+()*)+45591ᙊḄᨵᐵᭆ_?ឋ=45521*)+46715ᳮ78ூᑖ᪆᪷;ᙊᕜ)\ᳮC`a403,᪷;2Ὺ*)+Ḅឋ=C`a30=NB4O,᪷;*)+ᑁ)c\ᳮC`ᓽB.ூEFE1ZACB=54°,ᙊY)ZAOB=2ZACB=108°,OB^OA,ZABO=ZBAO=4x 180dZAOB6=36°,ᦑ⌱1C.ூJK⚪ὃLMᙊᕜ)\ᳮᙊY)ஹஹefḄᐵZ2Ὺ*)+Ḅឋ=c*)+Ḅᑁ)c\ᳮ2gh7C`ᙊY)NAOBḄWᦪEi⚪ḄᐵQ.3. 2020ᵞᾓlmஹ
36o9,3ᑖAOd( AC=2,AB=4,ᙠpqᑖ8C,ᑣDCḄ!
37A.2>/2B.MC.275D.᧼ூὃM51ᙊᕜ)\ᳮூ/⚪5591ᙊḄᨵᐵᭆ_?ឋ=455412Ὺ*)+()*)+4691rᵨthூᑖ᪆ᐜ᪷;ᙊᕜ)D1Nfl4C=NO=90᪷;vw\ᳮᓽBDxy.ூEFE1ᙠpqᑖ3C,/.BD=CD,BCOḄ( ZBAC=ZD=90°,AC=2,AB=4,BC=h+4=2,RtABDCDC2+BD2=BC2,2DC2=20,r>c=Vio,ᦑ⌱1D.ூJK⚪ὃLᙊᕜ)\ᳮvw\ᳮ2ghE⚪ḄᐵQᮣ|}ᵨᡠghE⚪,ᑭᵨvw\ᳮC.Ḅ!ὃ ὃ⚪.8.1. 2020ᓭT7,4ᑖOḄ( 8=20,OḄAB1CD,ᚖM,QW:OC=3:5,ᑣA3Ḅ!A.8B.12C.16D.2B
38ூὃM21ᚖ \ᳮ4KQvw\ᳮூᑖ᪆4ᐜ᪷;OḄ( C£>=20,QW:O£>=3:5C`?Ḅ!᪷;vw\ᳮBC`AMḄ!D`xy.ூEFE14,OḄ( C£>=20,OM:OD=3:5,:.OD=10,OM=6,ABVCD,AM=>JOA2-OM2=V102-62=8,:.AB=2AM=16.ᦑ⌱1C.ூJK⚪ὃLḄᚖ \ᳮ᪷;⚪t¤`¥¦.᪀⌼`()*)+EFi⚪ḄᐵQ.1.2020©ªT9,3ᑖAஹBஹCᙠCDYOA,CE±OB,ᚖᑖஹE, NZ>CE=4OᑣNAC3ḄWᦪA.140°B.70°C.110°D.80°ூὃM2ᚖ \ᳮ4M5ᙊᕜ)\ᳮூ/⚪5591ᙊḄᨵᐵᭆ_?ឋ=46715ᳮ78ூᑖ᪆ᐜ᪷;µ-+Ḅᑁ)c360C4403=360-90-90-40=140ᵫ·ᡠ¸Ḅᙊᕜ)ᙊY)Ḅd BDḄWᦪᨬºᵫµᐳᙊḄឋ=Dxy.ூEFE1ᙠA5¼dP,AP,BP,CDYOA,CEYOB,
39ZODC=ZOEC=90°,ZDCE=40/.ZAOB=360°-90o-90o-40o=140°,ZP=-ZAOB=70°,2AஹCஹBஹPµᐳᙊ/.ZP+ZACB=180°.ZACB=180°-70o=110°,ᦑ⌱1C.ூJK⚪ὃLḄᙊᕜ)\ᳮ¾gᙠ·ᙊᡈ2ᙊ·ᡈ2ᡠ¸Ḅᙊᕜ)2,À2Áᩩᡠ¸ḄᙊY)Ḅd EFi⚪ḄᐵQ.2. 2020ᔡT6,2ᑖµ-+/WCZᑁ NB=108ᑣNOḄᜧÅA.54°B.62°C.72°D.82°ூὃM5ᙊᕜ)\ᳮ4M6ᙊᑁµ-+Ḅឋ=ூ/⚪691rᵨth45591ᙊḄᨵᐵᭆ_?ឋ=ூᑖ᪆}ᵨᙊᑁµ-+¸)Æ⊡ÈÉᓽB.ூEFE1µ-+438ᑁO,=108.-.ZZ)=180o-ZB=180o-108o=72o,ᦑ⌱1C.
40ூJK⚪Ê⌕ὃLMᙊᑁµ-+Ḅឋ=¾ÌÍÎᙊᑁµ-+¸)Æ⊡EFi⚪ḄᐵQ.ÏஹÐÑ⚪I. 2020µÒᓭᐙT16,4ᑖÔABCᑁABḄ( ÕÔABCÖC×ØᑮÔÚ>4,EᙠÛgAE=2,tanO=3,ᑣAB=—.—3—ூὃM51ᙊᕜ)\ᳮ4MA1*)+ḄᙊY4R21×ØḄឋ=4T71E()*)+.ூ/⚪5591ᙊḄᨵᐵᭆ_?ឋ=46715ᳮ78.ூᑖ᪆᪷;ᙊᕜ)\ᳮDᑮ/AEB=/ACB=90᪷;×ØḄឋ=Dᑮ4C=CE,BC=CD,NACE=NBCD,ZECD=ZACB=90°,ÝCE=3x,CD=x,ᵫvw\ᳮDᑮDE=V10x,᪷;Þ*)+Ḅឋ=DᑮBD=-᪷;vw\ᳮᓽBDᑮxy.3ூEFE1Ḅ( /AE8=NAC8=90•.•ÕÔABCIC×ØᑮÔEDC, .AC=CE,BC=CD,/ACE=NBCD,ZECD=ZACB=90°9CEVtan£>=---=3,CD , ÝCE=3àCD=x, .DE=4WX,VZACE^ZBCD,ND=NABC=NAEC,AACf^ADCB,.AC_CE_AE_AE=2,
412:.BD=-3 .BE=DE-BD=V10x-3• AE1+BE2=AB2,.-.22+(VioX--)2-(VlOx)2,3,_Vlo•.x---------,310 .AB=DE=—,3ᦑFᫀ1——.3ூJK⚪ὃLM*)+ḄᙊYÞ*)+Ḅᑨ\cឋ=*)äᦪḄ\åvw\ᳮæOḄh+E⚪ḄᐵQ.2.(2020µÒᥤèéT15,4ᑖ)Ûg┦)*)+ABCᑁ 2ḄO,ODLBCஹD,ABAC=60°,ᑣ/)=1.ூὃMA *)+ḄᙊY4M2 ᚖ \ᳮ4M51ᙊᕜ)\ᳮ4KQ vw\ᳮூ/⚪5591ᙊḄᨵᐵᭆ_?ឋ=46715ᳮ78ூᑖ᪆03cOC,᪷;ᙊᕜ)\ᳮD`4OCḄWᦪí;2Ὺ*)+Ḅឋ=DᑮN88ḄWᦪxᔠ()*)+Ḅឋ=BD8.ூEFE1OBcOC,AABCᑁ 2ḄO,N84C=60.-.ZBOC=120°,OB=OC=2,ODVBC,OB=OC,ZBOD=ZCOD=60°,:.ZOBD=30°,
42OD=-OB=\,2ᦑFᫀ11.ூJK⚪ὃLMᙊᕜ)\ᳮஹ*)+ᙊḄឋ=ஹ2Ὺ*)+*.ᔠdஹ30Ḅ()*)+Ḅឋ=2ghE⚪î◤⌕ðñ¥¦.ò}ᵨᙊᕜ)\ᳮ.3.2020óôõö÷øRùT16,4ᑖòdᙽ 1ñḄᙊ+ûüý`dþᙊᕜ)120Ḅᡧ ABC,ᩭḄᡧ ᡂᙊ┵ᑣᙊ┵Ḅ☢ᙊḄ- -3ூὃ!M5%ᙊᕜ'(ᳮ*MP%ᙊ┵Ḅ,-.ூ/⚪55B%123 4ᙊ*55C%4ᙊᨵᐵḄ,-*55F%ᢗ94:;*64%>?@A*66%B-CD*69%FᵨHI.ூᑖ᪆LM▢9ᡧ ḄOPQRSLMᡂᙊ┵Ḅ☢.ூTUT%ᵫ⚪HW▢9ᡧ Ḅ1”ᙊZ'Ḅ[ᦪ120,1*1ᑣᡧ ḄOP%180Rᡧ ḄOPabcᡂᙊ┵Ḅ☢ᕜPdeᨵ%120nxl2"=-------,180TWr=—f3ᦑUᫀ%—.3
43ூ!no⚪ὃpᙊ┵Ḅᨵᐵ,-qrᡧ ḄOPabcᡂᙊ┵Ḅ☢ᕜPsTtu⚪Ḅᐵv.4. 2020•xᓅz{T12,3ᑖ|;!A,B,Cᙠ~sNB4CḄ'ᑖNBOC=120ᑣḄ[ᦪ_30_.ூὃ!M4%ᙊZ'ஹOஹḄᐵ*M5ᙊᕜ'(ᳮூ/⚪559%ᙊḄᨵᐵᭆឋ*69%FᵨHIூᑖ᪆ᐜ᪷ᙊᕜ'(ᳮWᑮNR4C=4/BOC=60ᯠᑭᵨ'ᑖḄ(r(2NC4£Ḅ[ᦪ.ூTUT%ABAC=-ZBOC=-x120°=60°,22R4sABACḄ'ᑖZCAD=-ZBAC=30°.2ᦑUᫀ30.ூ!no⚪ὃpᙊᕜ'(ᳮ%ᙠᙊᡈᙊOᡈOᡠḄᙊᕜ'acᩩOᡠḄᙊZ'Ḅ.5. 2020•,T14,3ᑖ|;ᙠ!AᙠBC~ZBOC=100°.ᑣN8AC=ூὃ!M4%ᙊZ'ஹOஹḄᐵ*M5ᙊᕜ'(ᳮூ/⚪55C%4ᙊᨵᐵḄ,-*67%¡ᳮCDூᑖ᪆᪷ᙊᕜ'(ᳮ¢ᙊᑁ¤¥3 ḄឋᓽSWᑮ§¨.ூTUT%;©O~Ḅ!ª¤F|CD,
44ZBOC=100°,...NO=50°,/.ABAC=180°-50°=130°,ᦑUᫀ%130.ூ!no⚪ὃpᙊᕜ'(ᳮ4ᙊᑁ¤¥3 Ḅឋ1r«M¬sT⚪Ḅᐵv.6. 2020®¯¯°ᙢ²T16,3ᑖ|;4sAABCḄ¤ᙊḄ@ZBAD=40°,ᑣNACB=50°.ூ/⚪67%¡ᳮCD*559%ᙊḄᨵᐵᭆឋூᑖ᪆ª¤ᓽ;᪷ᙊᕜ'(ᳮᓽSWᑮ§¨.ூTUT%ª¤´µ,;A£A4BCḄ¤ᙊḄ@:.ZABD=90°,ZD=90°-Z£L4£=90°-40°=50°,:.ZACB-ZD=5Q°.ᦑUᫀ50.ூ!no⚪ὃp¶' Ḅ¤ᙊ4Zᙊᕜ'(ᳮ%ᙠᙊᡈᙊOᡈOᡠḄᙊᕜ'acᩩOᡠḄᙊZ'Ḅ.7. 2020®¯ᱝ¸T5,3ᑖ|sOḄOMYAB,ᚖºM,ª¤Q4.
45AAOWᨵ's30OM=2J,ᑣA3ḄP12ᡈ4.ூὃ!KQ ½¾(ᳮ*M2 ᚖ(ᳮூ/⚪32%ᑖ¿À¨%64%>?@Aூᑖ᪆ᑖNO4W=30NAOM=30ÂÃÄÅᑖÆᑭᵨ1ᑗḄ(LTᓽS.ூTUÈT%OM±AB,..AM=BM.NQ4M=30ᑣtan“AM=^=^=@,AMAM3...AM=6,ZAQW=30,AMᑣtanZ.A0M=OM263/.AM=2, .AB=2AM=4.ᦑUᫀ%12ᡈ4.ூ!no⚪ὃpᚖ(ᳮ¶'ÑᦪT⚪Ò⌕᪷⚪HᑖÄÅÀ¨.
468. 2020xᓅ឵Õ{T15,3ᑖ|;Ö×ᙊḄ@A5=4,!Cᙠᙊ~Ø!AᙊZACÙOÚABc!O,ª¤8c.NA8C=60ᑣ;▢9ÛᑖḄ☢Ü_2Ý-Þߧà©áâã|ூὃ!MO-.ᡧ ☢ÜḄ,-*1"%áâᦪ¢ᨵᦔᦪåூ/⚪554%Ὺ¶' 4@'¶' %55C%4ᙊᨵᐵḄ,-*559%ᙊḄᨵᐵᭆឋ*66%B-CDூᑖ᪆᪷60ᱯè'LMAC¢8C,é-MA48CḄ☢Ü᪷ᡧ ☢ÜêëLMᡧ CWḄ☢Üéᵨ¶' Ḅ☢Üìíᡧ ☢ÜᓽS.ூTUT%4?s@îZACB=90°ZABC=60°L.\ZCAB=30°LBC=-AB=2,AC=2g,25MBe=gïBC= 2ð2=26,NOW=30ᡧ AC£Ḅ☢Ü=AC? 2x/32=%▢9ÛᑖḄ☢Ü2&-%.ᦑUᫀ%2#-ñ.ூ!no⚪ὃpᙊᕜ'(ᳮT@'¶' ᙊ¢ᡧ ☢ÜḄ§ᔠᐵvᙠcᑭᵨᙊᕜ'Ḅឋóᑮ@'¶' ô§ᔠᡧ ☢ÜêëTM.9. 2020•õ°öᜮTI6,4ᑖ|;øᙽ⊈Ḅᙊ ûü~Mᙊᕜ'120°Ḅᡧ ABC,ᩭḄᡧ ᡂᙊ┵ᑣᙊ┵Ḅ☢ᙊḄ--3m.
47BCூὃ!M5%ᙊᕜ'(ᳮ*MP%ᙊ┵Ḅ,-.ூ/⚪55B%123 4ᙊ*55C%4ᙊᨵᐵḄ,-*55F%ᢗ94:;*64%>?@A*66%B-CD*69%FᵨHI.ூᑖ᪆LM▢9ᡧ ḄOPQRSLMᡂᙊ┵Ḅ☢.ூTUT%ᵫ⚪HW▢9ᡧ Ḅ1ἔᙊZ'Ḅ[ᦪ120120Þx1ᑣᡧ ḄOP%——,180Rᡧ ḄOPabcᡂᙊ┵Ḅ☢ᕜPdeᨵ%120zrxl2nr=-------L180r=L3ᦑᫀ—.3ூ⚪ὃ ᙊ┵Ḅᨵᐵ#$%&ᡧ(Ḅ)*+,-.ᡂᙊ┵Ḅ0☢ᕜ*345⚪Ḅᐵ6.10.82020•:;<ᜮT17,4ᑖCᨵDEFG☠ᙠGJᜋ☢ḄLMNᙠOPDQRSSTUV-LMNWXḄὁZ[\]ὁZ^_ᨬabᡫᣍ.eᜋ☢ஹLMஹRgὁZhᳮjᓄlDm☢ᑁḄoᡈqrtNABC=90°,M,Nᑖ|ᙠ}o54,BCMN*ᢝMN=4,EMNḄWᑮBA,BCḄ^_ᑖ|4g2.ᙠPWR]ὁZḄ^_EḄᨬa_26-2.ூὃKPGJJ(ḄWoM8]ᙊḄVᐵ.
48ூ⚪25r552J(69ᵨ.ூᑖ᪆tBE,BD.¡¢BE,BD,᪷¤-8E¡ᓽ¦.ூtBE,BD.ᵫ⚪BD=V22+42=2>/5,•NMBN=9G°,MN=4,EM=NE,:.BE=LMN=2,2EḄ¨©ª3«Bᙊ¬2®Ḅᙊ,¯,E°ᙠo±8bDEḄᨬa.♦•DEḄᨬa2⌲-2.ᦑᫀ2⌲-2.ூ⚪ὃ ]ᙊḄVᐵGJJ(WoḄឋ´[µ⚪Ḅᐵ63ᮣ·¨ᵨᡠ¹µ45⚪º-Wὃ»ὃ⚪r.11. 2020•¼½¾¿T17,4ᑖCtÀ(ABCWE3ABDE,ÁÂ4OEÃEÄᢚាÇÈA°ᙠBCḄWFᜐᙠOFÊO,«Oᙊ¬ᔆ*4Ì®Íᙊ]CD+ᑗ-G.ÏAO=4,ᑣtW▢ÒÓᑖḄ☢Ô_ÕD_.ூὃLBÀ(Ḅឋ´MCᑗoḄឋ´MOᡧ(☢ÔḄ#$PBÄᢚᣚ8ᢚ×5⚪C.
49ூ⚪11#$⚪556À(Ø(NÙ(558mÚஹÛÜ]ÝÞ55A]ᙊᨵᐵḄVᐵ66¨$ßà67áᳮßà.8ᑖ᪆â0G,ã%ÂDOGsXDFC,¢r=äå0G=æ=*,ᑣ—=-,DFFC424¡¢ᙊḄ®Dã%^OF[J(ᑣ¦ᵫᡧ(Ḅ☢ÔèégJ(Ḅ☢Ô3èé¡¢ᫀ.ூ0G, ,ÁÂADEÃDEÄᢚាÇÈA°ᙠ8cḄWæᜐ, .AD=DF=4,BF=CF=2,• •À(ABCWNDCF=90, .ZFDC=30°, .Z£)FC=60°, ]CO+ᑗ-G,:.OGCD,VBC1CD,:.OG//BC,:.ADOGSADFC,,DOOG••--=9DFFC4--xxåOG=OF=ëᑣ----=D4244x=-,ᓽḄ®3D.330ÍOH_LFQ,VZDFC=60°,OF=OQ, ./\OFQ[ÂlᳮÂOGQ[Â
50A/32V3.ZGOQ=ZFOQ=60°,0H=OQ=W-sᡧ(OGQ=Sᡧ(OQFVS▢Ò= SÀ(OGCH-Sᡧ(OGQ-§ÂOQHC+ Sᡧ(OQæDOFQC342733142A/34GX=SÀ(OGCH~-SAOFQ=-x----------- -X—X---------==-----------.23322339ᦑᫀ----.9ூ⚪ὃ íᡧ(☢ÔḄ#$ᑗoḄឋ´Äᢚᣚîïðñòt(Ḅឋ´3⚪Ḅᐵ6.12.82020•¼½¾¿T17,4ᑖCtÀ(ABCQWEABDQE,ÁÂAOEÃEÄᢚាÇÈA°ᙠBCḄWæᜐᙠæÊO,«Oᙊ¬æ*4J3®Íᙊ]8+ᑗ-G.ÏAD=4,ᑣtW▢ÒÓᑖḄ☢ÔூὃLBÀ(Ḅឋ´MCᑗoḄឋ´MOᡧ(☢ÔḄ#$PBÄᢚᣚ8ᢚ×5⚪C.ூ⚪11#$⚪556À(Ø(NÙ(558mÚஹÛÜ]ÝÞ55A]ᙊᨵᐵḄVᐵ66¨$ßà67áᳮßà.öᑖ᪆âOG,ã%ÂOOGs/\OFC,¢r=åOG=OF=x,ᑣ=-,DFFC424¡¢ᙊḄ®ã%Âæ[J(ᑣ¦ᵫᡧ(Ḅ☢ÔèégJ(Ḅ☢Ôèé¡¢ᫀ.ூOG,
51*.•ÁÂAOEÃOEÄᢚាÇÈA°ᙠ8CḄWæᜐ.AD=DF=4BF=CF=2,f• •À(ABCWZDCF=90°,AZFDC=30°, • ZDFC=60°, 0]+ᑗ-G,.OGA.CD,•:BCLCD,.OG//BC,:.DOGS&DFC, DOOG••-----=------fDFFC4—xxåOG=OF=x,ᑣD-=4244x=—ᓽOḄ®3D.33OÍûLFVZDFC=60°,OF=OQ,ÂæQ[ÂlᳮÂOGQ[Â/.ZGOQ=ZFO0=60°,0H=0Q=,Sᡧ(OGQ=Sᡧ(OQF,: S▢Ò=8SÀ(OGCH-Sᡧ(OGQ-SAOQH + Sᡧ(OQF-SAOFQ 34263142Gஹ46=SÀ(OGCH--SAOFQ=-X--------—— ——X—X--------=-------.23322339473ᦑᫀ9.
52ூ⚪ὃ íᡧ(☢ÔḄ#$ᑗoḄឋ´Äᢚᣚîïðñòt(Ḅឋ´3⚪Ḅᐵ6.13.82020•ᜩýT18,3ᑖCtᙠþÿ Ḅ1ḄAA8CḄ⚔A,Cᙳᙠ5ᙠ43=*.3I"#ACḄ$%_'_.II"(8C)*Ḅ+ᙊ-AC./%1P,ᑖ4AC,Ḅ568P+PQ9:ᨬ <=>ᵨ@ABḄ)CᙠEᡠGḄHIP,Q,JK⌕MNPḄOPQRSᑮḄU⌕VWN"—.ூὃN3\E-^ᩖ\E`PAabc-ᨬdef⚪`KQ-.hijᳮ`M5ᙊᕜmjᳮூn⚪66pqrst`64puR)v`558pwxஹz{-bc`13p\E⚪ூᑖ᪆I"ᑭᵨ᪷hijᳮᓽVI#ACḄ`II"9M,N,»J-./%C,-+ᙊ./%E,-AC./%P,PJ-8C./%ᓽ:Q.ூpI"#ACḄ$%ᵨ=`II"E9ᵨN,MV,
53J-MN./%ᨴC,-+ᙊ./%E,5E,-AC./%PJ-8C./%Q,ᑣPQᓽᡠV.ூ⚪ὃ\E-^ᩖ\Eஹhijᳮஹᙊᕜmjᳮஹabc-ᨬdef⚪⚪ḄᐵQabcឋ.14.(2020¡T15,3ᑖ)Eᙠ£A3CD(A3)*Ḅ+ᙊO¤¥ஹC,D.AC-./%E,82=34,ᑖ4¦§./%P,PB=BO,CD=2P.ᑣBOḄQ4.ூὃS9p.¨©mḄᑨj-ឋ`M5pᙊᕜmjᳮூn⚪67p«ᳮstp559pᙊḄᨵᐵᭆ®¯ឋp55DpEḄ.¨ூᑖ᪆ᵫCD,=CEC4±ZACD=ZDCE,ᑨ²ACAD^ACDE,:ᑮZCAD=ZCDE,³᪷ᙊᕜmjᳮ:NC4Q=NCB£>,ᡠ(N8B=NC8Q,%Qᑭᵨ$Ὺ©mḄᑨjBC=DC,µOC,E¶Ḅ+*r,ᐜWNOC//4),ᑭᵨw¸ᑖ#ᡂºjᳮ:ᑮ»=¼=2,½IJ=20)=4",ᯠÀWNᑭᵨ.¨CDOA:⌳=³ᑭᵨºḄឋÃrIrḄ<.3r6V2ூpµOC,ECDCA~CE~~DCÄNACD=ZDCE,
54:.\CAD^^CDE,/CAD=/CDE,NCAD=/CBD,:.ZCDB=ZCBD,/.BC=DC;¶Ḅ+*CD=CB,..CD=CB,:.ZBOC=ZBAD,:.OC/IAD,PCPO2rÅ/.——=——=——=2,CDOArPC=2CD=4Q,/PCB=/PAD,/CPB=ZAPD,:."CBs"AD,.PCPB4>/2rPAPD3/-6>/2.\r=4,;.OB=4,ᦑᫀ4.ூ⚪ὃ.¨©mḄᑨj-ឋp©m.¨ḄᑨjÈ)QὃὃḄÉÊ--ᙠᑨjËÌ©m.¨=ÍÎÏᑭᵨEÐᨵḄÑᐳmஹÑᐳ$◚ÔᩩÖ(ᐙᑖØᢵÚEḄ\ᵨÛS.¨©mḄÈÜÝQÞ¥\w¸᪀⌼.¨©m`ᡈâÚEbEã¸ᑖஹäᔠ`ᡈ\æç᪀⌼.¨©mᑨj©m.¨ḄÝᨵ=ᓫéêᵨᨵ=◤⌕ìᔠqᵨ@íQᓫéêᵨîQìᔠqᵨï⌕ᐹᜓÍᨵḄᩩÖ.òὃᙊᕜmjᳮ.15. 2020óôT14,3ᑖ"Eᙠ£Q48cõᙠAmC,ᑣNADCḄBᦪQ_60
55oBூὃL8põḄឋ`M5pᙊᕜmjᳮூn⚪67p«ᳮst`559pᙊḄᨵᐵᭆ®¯ឋூᑖ᪆᪷õḄឋ:INB=ZAOC,᪷ᙊᑁ£Ḅឋ:INB+"=180ᓽ:I"+NAOC=180᪷ᙊᕜmjᳮ:I3/0=180ᓽV:NADC=60.ூp£A8CDᑁ%O,:.ZB+ZD=180°,£øCõ:.ZB=ZAOC,.\ZD+ZAOC=]80P,ZAOC=2ZD,.•.3"=180,.-.ZAL>C=60°.ᦑᫀ60.ூ⚪ὃᙊᕜmjᳮᙊᑁ£ḄឋõḄឋùúឋjᳮQ⚪Ḅᐵ.16. 2020ûüTl,3ᑖ"ᙠAABC1AB=6,ZACB=45°.ᑣA4BCḄ☢þḄᨬᜧ _90+9_.ூὃMAḄᙊJ4ᚖᨬKQᳮM5 ᙊᕜᳮM2ᚖ ᳮூ ⚪67 ᳮ!559ᙊḄᨵᐵᭆ%&ឋ(ூᑖ᪆✌ᐜ-C./M,ᵫ123456⌕8A4BCḄ☢:ᨬᜧ4<⌕CM=ᨬᜧ ᓽ54ᓽ56?CM-ᙊO@4CMᨬᜧ4ᯠBᵫᙊᕜᳮ4C6A4O3DEῪG4ᑣ5I6CMḄJ4KLI6Mᫀ.ூPMP.AABCḄᙊO,-C./M,
56.••⌕8AABCḄ☢:ᨬᜧ4<⌕CM=ᨬᜧ ᓽ54SᡠU4?CM-ᙊO@4CMᨬᜧ4CM±AB,CM-O,..AM=BMVᚖ ᳮW4AC=BC,ZAOB=2ZACB=2x45°=90°,:.OM=AM=-AB=-x6=3,22:.OA=\IOM2+AM2=3>/2,CM=OC+OM=3y/2+3,5cCM=x6x 3X+3=9Z+9.aAeᦑMᫀ9\+9.ூ]^⚪ὃ_`Ḅᙊ4ᙊᕜᳮa&EῪGឋ(.bc6ᑮ?CM-ᙊO@4CMᨬᜧDᐵe.1. 2020•⎎ghi T13 3ᑖWS4■DḄG 41CD_LAB,ᚖlE,ZBC»=304CD=2)ᑣ▢noᑖ☢:5p=—.ூὃM2ᚖ ᳮMOᡧ☢:ḄtuKQᳮA/5ᙊᕜᳮூ ⚪69Zᵨcw55CᙊᨵᐵḄtu
57ூᑖ᪆xOC.CyOC//BO, zS▢=5ᡧ0{ᓽ5P|}⚪.ூPMPxOC.ABA.CD,:.BC=BD,CE=DE=B/COD=/BOD,ZBOD=2ZBCZ)=60°,/.ZCOB=60°,OC=OB=OD,:.\OBC,~08DE,:.OC=BC=BD=OD,.• OC3OD4.\OCHBD,-SMDC=S"OD9...S▢=Sᡧ0W4EDOD==2Lsin60°60•2360ᦑMᫀ.3ூ]⚪ὃ_ᡧḄ☢:4Ḅᑨឋ(4Ḅᑨឋ(Ew4P⚪ḄᐵeDᵨᓄḄὃ}⚪4/ὃὃ⚪.2. 2020•⎎ghi15 3ᑖWS4ᙠEAABC4=6,£>,£ᑖᙠBC,AC4BE>=CE,x4,BEஹF,xCF,ᑣCFḄᨬ¡ D_26
58EBDCூὃKD ᐰEḄᑨឋ(KK EḄឋ(ூ ⚪553SḄᐰE69Zᵨcwூᑖ᪆✌ᐜCyZARB=1204 z®Ḅ¯°±²DOᙊ4´ Ḅµ¯°(NAO8=120,04=26)4x0c¼ON,?”N¾ᔠ@4BḄ ᨬ¡.ூPMPS4AABCDE4.\AB=BC=AC,ZABC=NBAC=ZBCE=6(T,BD=CE,:.^ABD=\BCE(SAS):.ZBAD=ZCBE,ÁZAFE=ABAD+ZABE,TZAFE=NCBE+ZABE=ZABC!.•.NAFE=604.\ZAFB=120°,.•.FḄ¯°±²DOᙊ,OA´ Ḅµ¯°(NAO8=120,04=26),xOC¼/N,?®N¾ᔠ@4CFḄ ᨬ¡4ᨬ¡ =OC-ON=46-26=20.ᦑMᫀ2\/3.ூ]⚪ὃ_ᐰEḄᑨឋ(ஹEḄឋ(ஹᙊḄᨵᐵwEw4P
59⚪ḄᐵeDÇÈÉÊᙊP|}⚪4/ὃËÌ⚪ḄÍÎ⚪.1.V3ᑖWV2020•ÏÐÑWS4ADDA4BCḄᙊOḄG 4ÓNE4T>=404ᑣZACB=50°.ூὃMAḄᙊூ ⚪67 ᳮ!559ᙊḄᨵᐵᭆ%&ឋ(ூᑖ᪆xᓽ4S4᪷Øᙊᕜᳮᓽ56ᑮÙÚ.ூPMPx84S4A£>AABCḄᙊḄG 4/.ZABD=90°,/.ZD=90°-Z&4£W=90°-40°=50°,ZACB=ZD=50°.ᦑMᫀ50.ூ]⚪ὃ_`Ḅᙊ4ᙊᕜᳮᙠÝᙊᡈEᙊ4ݵᡈEµᡠßḄᙊᕜàE4E/áᩩµᡠßḄᙊḄã´.1.V2020äᓭæ□4T16,4ᑖWS448´ᙊḄG 4M,CD´ᙊḄEᑖ4AB=8,´ᙊOàᑗ/8.PAMã°VëA,M¾ᔠW4GPCBDஹD,BELOCE,ìJ3E¼PC/F,ᑣíᑡÙÚï3ḄDঝটঠ.Vᑏzᡠᨵï3ÙÚḄôõWজPB=PD ঝ8cḄJ4öV3WZDBE=45°®ABCF^APFB-,ঠCFCP .3
60ூὃM2 ᚖ ᳮM5 ᙊᕜᳮMN-µJḄtuMC-.ᑗḄឋ(59à÷Ḅᑨឋ(ூ ⚪559ᙊḄᨵᐵᭆ%&ឋ(554EῪG55CᙊᨵᐵḄtu55D SḄà÷55AᙊᨵᐵḄøùᐵú66¯u!67 ᳮ!ூᑖ᪆জxAC,üìJAC,ḄìJ¼/4,PD=PB,6zPAMḄ4ý▭ëÿ ᓽᑨঝᐜ4OC,ᵫ8cḄ ᑨঞᵫN3OC=60 ᪷! "ᔠ$ឋ&NOBE,ᵫ Ḅ'(ᜧZDBE,)ᑨট+,NCPB=Na-=30 ᑭᵨᐳ ABC/SAPCB,)ᑨঠᵫ AOBC3c=08=4,ᵫ45 CPCP=,)ᑨ.ூ9:9<জ>?AC,@AAC,BCDḄA"EFG” J1,M,CKLᙊNḄ ᑖG .-.ZBAH=30°,BLᙊO4ᑗFG8..-.ZABD=90°,.-.ZH=60°,ZACP=ZABP,ZACP=ZDCH,ZPDB=ZH+ZDCH=ZABP+60°,ZPBD=90°-Z4B/>,ZPDB=ZPBD,ᑣNABP+60°=90-Z/WP,:.ZABP=15°,.•.PGAMḄRG SBPAMNḄ$TGUVᐰXᔠ NPDBU$FZABD,.,.P3U$FPD,ᦑজ┯ঝM,CKLᙊNḄ ᑖG ZBOC=-x180°=60°,3
61[\/W=8,,-.OB=OC=4,8cḄ=KI=3ᦑঝ];J1ঞZBOC=60°,OB=OC,:.ZABC=60°,OB=OC=BC,BEIOC,•,.NOBE=NCBE=30°,ZABD=90°,NDBE=60°,ᦑঞ┯টMஹNKA3Ḅ ᑖG /.ZBPC=30°,ZCBF=30°,. ./CBF=/CPB,ZBCF=ZPCF,;NCFs"CB,ᦑট]ঠABCF^APCB,.CBCF~CP~~CB':.CFCP=CB?,CB=OB=OC=-AB=4f2/.CFCP=16,ᦑঠ].
62ᦑ:ᫀ<ঝটঠ.ூG`a⚪c⌕ὃfgᑗ"Ḅឋ& ᙊᕜ ᳮ [ Ḅឋ& Ḅឋ&Bᑨ Ὺ Ḅឋ& 45 Ḅឋ&Bᑨ ᐵlKmnopSqឋ& @rᮣtuᵨ.1.w2020z{|}~ T16,3ᑖDJ 4DKAAfiCḄ?ᙊOḄ[\ /BC4=5O ᑣZ4T>8=50ூὃGMA-. Ḅ?ᙊBூ⚪67<ᳮr<559<ᙊḄᨵᐵᭆឋ&ூᑖ᪆᪷!ᙊᕜ ᳮᓽᑮ.ூ9:9<4DKAABCḄ?ᙊOḄ[\ .,.GA,B,C,ᙠON ZBG4=5O°,:.ZADB=ABCA=5O°,ᦑ:ᫀ<50.ூG`a⚪ὃfg Ḅ?ᙊB ᙊᕜ ᳮ mnopᙊᕜ ᳮK9⚪Ḅᐵl.2.1.w3ᑖDw2020|¢ᓭ¤ T12,3ᑖD¥¦ḄL\13§ ¨A3Ḅ10a” ᑣᙊOᑮABḄª«12cm.ூὃGM2 ᚖ\ᳮKQ ®ᳮூ⚪30<ᙊḄᨵᐵឋ&23<[ B®ᳮ<69?4,᪷!ᚖ\ᳮᑮAC=BC=LA5=5,ᯠµ2ᑭᵨ®ᳮ¶·OCḄᓽ.ூ9:9<J ±OCL45FC,>?4,ᑣAC=BC¸AB=5,2
63ᙠRtAOACR OC=413?-5?=13,ᡠºᙊOᑮABḄª«12cm.ᦑ:ᫀ12.ூG`a⚪ὃfgᚖ\ᳮ<ᚖ[F¨Ḅ[\»ᑖSᩩ¨ @½»ᑖ¨ᡠ¾Ḅ¿ᩩ.1. 2020ÀÁ T12,3ᑖDᡃÃÄÅᦪÇÈᐺ℉±ËÌÍ·ÎÏRÐÑg$Ò“ᙊᩞÕÖ”Ḅ×⚪<“ØᨵᙊᩞÕᙠÖR U¦ᜧÚ.ºÛÛÜ Ý$Þ Û⍝$à.×\áâ㔯äK<Øᨵ$ᙊå ᩈᩞ ÕᙠᜋÖR U¦ᐸᜧÚ.ᵨÛéÛSᩈᩞ ÛêÝᓺ=1Þ Û⍝9=1à 1à=10ÞD.×S᪷ᙊ ᩈᩞḄ[\K26Þ.ூὃG1O<ᦪÇì°M3 ᚖ\ᳮḄuᵨூ⚪559<ᙊḄᨵᐵᭆឋ&67<ᳮrூᑖ᪆᪷!⚪¯45,ᵫᚖ\ᳮ==1à=5Þ íL\22OA=OE=r,ᑣ£D=ï-1,ᙠRtMMDR ᪷!®ᳮ649ᙊூ?⚪679@ᳮAB:5589!=#.ᙊ:5599ᙊḄᨵᐵᭆFGឋIூᑖ᪆2%OC,OD.KNCOZḄ5ᦪM᪷OᙊᕜᳮPKNCPDḄ5ᦪᵫᑁ>ᳮᓽSPKTU.ூV92%OCஹOD,ᡠX9!"#360°NCOD=——=72°,5NCPD=-ZCOD=36°,2DGVPC,.\ZPGD=90°,ZPDG=90°-Z.CPD=90°-36°=54°,ᦑVᫀ*954.
65ூ)[\⚪ὃ]!=#>ᙊஹᙊᕜᳮ^_`⚪Ḅᐵabcde!"#ḄឋI>ᙊᕜᳮf&ὃgὃ⚪h.1. 2020ijT15,5ᑖ ᙠAABC#+Ḅ,)lAD*ḄOmAC&)E,2%AE.n.3coᑗZADE=55°,ᑣNCḄ5ᦪ*.ூὃ)M5.ᙊᕜᳮ:MC9ᑗrḄឋIூ?⚪669stAB:319ᦪTᔠ:679@ᳮAB:55A9.ᙊᨵᐵḄuvᐵw:5599ᙊḄᨵᐵᭆFGឋI:179@ᳮxy⚪ூᑖ᪆ᵫᡠzḄᙊᕜ*PNA£D=90ᵫᑗrḄឋISPNAOC=90ᯠᵫ{Ḅ|o^SPNC=NA0E=55.ூV9AD*OḄ:.ZAED=90°,.-.ZADE+ZDAE=90°i.8coᑗ.-.ZADC=90°,:.ZC+ZDAE=90°,.-.ZC=ZADE,ZADE=55°,:.ZC=55°.ᦑVᫀ*955°.ூ)[\⚪ὃ]}ᑗrḄឋIஹᙊḄoᐵᭆFGឋIG~|ᐵw^_`)bcdeᙊḄoᐵឋI⚪Ḅᐵa.
662. 2020ᙢ,T16,3ᑖ4A4BCḄ%ᙊOḄn/&4=40ᑣZACB=50°.ூὃ)MA-.Ḅ%ᙊ.ூ?⚪679@ᳮAB:5599ᙊḄᨵᐵᭆFGឋIூᑖ᪆2%3D,᪷OᙊᕜᳮᓽSPᑮT.ூV92%ᓽ,AD*AABCḄ%ᙊḄ,.'.ZABD=90°NO=90°—N=90°—40°=50°,:.ZACB=ZD=50°.ᦑVᫀ*50.ூ)[\⚪ὃ]}Ḅ%ᙊ.ᙊᕜᳮ9ᙠ{ᙊᡈ^ᙊ{ᡈ^ᡠzḄᙊᕜo^^&ᩩᡠzḄᙊḄ,.1. 2020•ₚ T15 3ᑖ ᡠXḄᡧAO804=08=2,ZAOB=9Q°,C0+,)NAOC=302%8C,C4ḄᚖrmAO&)ᑣ▢ᑖḄ☢ூὃ)MO-.ᡧ☢Ḅt:KW ^Ὺ:M5 ᙊᕜᳮ
67ூ?⚪669stAB:5599ᙊḄᨵᐵᭆFGឋIூᑖ᪆᪷OᡧḄ☢ᑭᵨ▢ᑖḄ☢=S-S,+S.8D¢£t em0BCூV99/AOB=90°,ZAOC=30°,N80c=60°,ᡧAO8OA=OB=2,:.OB=OC=2,ABOC^#•.,COAḄᚖrmAO&)O,;.NODC=90°,AZAOC=30°,hτ:.OD=—OC=y/3,CD^-OC=\,22▢ᑖḄ☢=SᓭΊ-SAOBC+S&CW0c[x2X2X┯ª!+┯ª!X┯ª!XI2V3=-7T------.32ᦑVᫀ*2-®.32ூ)[\⚪ὃ]}ᡧ☢Ḅt▢☢Ḅ¯⌕±²³/´ᑣ☢µᓄ*´ᑣḄ☢.¶ὃ]}^#Ḅᑨ>ឋI.4.1. 2020¸ᓭ¹ºT16,3ᑖ )PᙠlMN*Ḅᙊ+s»-)P/.M,N0ᔠ PQLMN,NEᑖNMNP,mPM&)E,mPQ&)¼.,ஹPFPE(1)-------1---------PQPM(2)Pl^=PM MN,½—NQ~2ூὃ)M59ᙊᕜᳮ:S99o¿Ḅᑨ.ឋI.
68ூ?⚪5599ᙊḄᨵᐵᭆFGឋI:55D9Ḅo¿:669stAB:679@ᳮAB.ᵪCFINNJூᑖ᪆(1)ÂÃÄPENS/XQFMP*■Ï,জÂÃÄNPQSAPMQ,PÒ_⁰,ঝMজXঝPÖ="MØÙÚÛSPTU:PMPQ(2)ÂÃÄNPQS/\MWP,P#=NQ MN,TᔠÞ_ᩩßPPM=NQ,M᪷OàMOPMᦪPl=9,¢ÒPMQ.NQḄâãM,ᐗåâãPVᫀ.NQMNூV9-1;MN*Ḅ, /MPN=90,æPQLMN,ZPQN=NMPN=90,■:NE[ᑖ/PNM, /MNE=NPNE,.APENS^QFN,]^,ᓽᙠ="জQFQNPNQN"?NPNQ+NNPQ=NPNQ+NPMQ=90,:"NPQ=NPMQ,'NPQN=NPQM=90°,:._NPQs/\PMQ,.PN_NQঝ,"~MP~~PQPEQF.•.জxঝP~PM~~PQ"QF=PQ-PF,PEQF_PF--------------1~PQPMPQ.PFPE••----1-----PQPM
69ᦑVᫀ*91;(2),:`PNQ=NMNP,ZNQP=ZNPQ,.4NPQsANMP,.PNQN.PN1=QN>MN,,:P#=PM MN,.PM=QN,,MQMQ'~NQ~~PMMQPM~MNPM.MQ_PM,•~NQ-MN.MQNQNQMQ+NQ,,èMQ2MQ.N=M(T+MQ-NQ,ᓽ1=,é=½ij/+x-i=o,NQJ5-IJ5+1Pᡈê=-ëì♦=X------------NQ2ᦑVᫀ*9ïð2ூ)[\⚪¯⌕ὃ]}ᙊḄឋIo¿ḄឋI.ᑨñᑖrḄòᐵaᮣôᙢØᣚÙÚ.5.1. 2020öj÷øT14,4ᑖ AABCḄᑁ%!)ᙊ)D,Eᑖùᙠ#AC,ABk,nD4=£B,ᑣN£>OEḄ5ᦪ1205.
70ூὃ)M4ᙊஹஹúḄᐵw:MAḄ%ᙊ.:KK^#ḄឋIூ?⚪5539Ḅᐰ^:679@ᳮAB:5599ᙊḄᨵᐵᭆFGឋIூᑖ᪆2%4,OB,᪷OÞ_ᩩßPᑮNAOB=120᪷O^ῪḄឋIPᑮNQ48=NO84=30᪷Oᐰ^ḄឋIPᑮNZXM=N8Oü&PᑮT.ூV92%4,OB,AABCOḄᑁ%!ZAOB=120°,OA=OB,ZOAB=ZOBA=30°,ZC4B=60°,/.ZO4D=30°,/.NOAD=NOBE,AD=BE,:.\OAD=\OBE{SAS),.\ZDOA=ZBOE,ZJDOE=ZDOA+ZAOE=ZAOB=ZAOE+/BOD=120°,ᦑVᫀ*9120.ூ)[\⚪ὃ]}Ḅ%ᙊ.^#ḄឋIᐰ^Ḅᑨ>ឋI,!ýḄKþÿ ᪀⌼ᐰ⚪Ḅᐵ.
712. 2020ᓭT19,3ᑖAfiᙊḄ AC=AD,OC=2,ZC4B=3O°,ூὃM5"ᙊᕜ$ᳮ&M2"ᚖ $ᳮூ(⚪559"ᙊḄᨵᐵᭆ+,ឋ.&67"/ᳮ01ூᑖ᪆ᙠῪAA85⚔44=30᧕89248=75&᪷;<=>9"ZOCA=^A=30°,ᵫ@>9NOCD=45°.ᓽACOE1Ὺ ᑣ£=E.ூF"AC=AD,ZA=30:.ZACD^ZADC=15°,AO=OC,.-.ZOCA=ZA=30°,:.ZOCD=45°,ᓽAOCEῪ ᙠῪRtAOCE5OC=2.G@OE=0.ᦑFᫀJ"&.ூLM⚪NᔠὃPQῪḄឋ.ஹḄᑁT$ᳮஹ UVḄWᵨ.6.1. 2020YZ[T13,4ᑖ\U43ᙊOḄ ]C£>AB,CD=8,ூὃKQ-.^_$ᳮ&JC `a bcḄde&M2"ᚖ $ᳮூ(⚪64"fg h&559"ᙊḄᨵᐵᭆ+,ឋ.ூᑖ᪆ijO”_LCDk”mnOC,᪷;ᚖ $ᳮ9ᑮCH=D”=4,p
72ᑭᵨ^_$ᳮrstOH=3,uv9ᑮCDwABbcḄde.ூF"ijk"mnOC,ᑣC”=O”=1c£>=4,2ᙠRtAOCH50H=^52-a=3,ᡠzCOwbcḄde3.ᦑFᫀJ3.ூLM⚪ὃPQᚖ $ᳮ"ᚖ k]Ḅ `ᑖ{ᩩ]}~`ᑖ]ᡠ=Ḅᩩ.2. 2020YZT14,4ᑖ\UḄ BCᑗk8,m1-J1nAC,OC.sinN8AC=-,ᑣtanZfiOC=—.ூὃT7 "MCᑗ Ḅឋ.&M5ᙊᕜ$ᳮூ(⚪55A"wᙊᨵᐵḄᐵ&67"/ᳮ01ூᑖ᪆᪷;ᑗ Ḅឋ.9ᑮ8 ,8C=x,AC=3x,᪷;^_$ᳮ9ᑮAB=>JAC2-BC2=73X2-X2=2bx,k9ᑮ•ூF"4?OḄ BCOᑗk3,.-.ABA.BC,:.ZABC=90°,,BC1sinABAC=---=-,AC3...3C=x,AC=3x,AB=\IAC2-BC2=73X2-X2=2y[2x,:.OB=-AB=y/2x,2tanZBOC=—=-^=—,OBbx2ᦑFᫀJ"—.2
73ூLM⚪ὃPQᑗ Ḅឋ. ᦪḄ$⚪Ḅᐵ.1. 2020TᱯT16,3ᑖ\UJOḄ ~J2r,CJO¡kA,BḄAOwiCḄOḄᑗ ¢ᚖ ᚖ£JO.জῪAOCḄ⚔J120¥¦ঝAAOCJ¨¦iJCD=@r,ঞῪAOCḄ=ª22«¬iᑣ,ট®Cᙠgᜐ°A4OC±ACᢚ³´$µᙠ 45ᐸ5¨·Ḅ¸¹Jঝঞট.ூὃM2 ᚖ $ᳮ&KH ῪḄឋ.&MC-.ᑗ Ḅឋ.&KK-.<Ḅឋ.&KO-.º30¥Ḅ &P2 «=ªḄឋ.&PB »ᢚ¼ᣚᢚ³¾⚪&M5"ᙊᕜ$ᳮூ(⚪67"/ᳮ01&14"¿À⚪&17"/ᳮÁÂ⚪ூᑖ᪆জiOjOE,AC,ᚖ£JE,8tNC4£>=309ᑮCO=ÃAC,pÄÀ2OE=-r,ᑭᵨNOCAwNCOE,ᑮCE#OE,ᓽ>ᑨÆ&ঝiAjA£_LOC,ᚖ£2E,¿ÀÇ<AECDJÈᓽ>ᑨÆ&ঞÉt¿ÀÇ<AOCZJÈᓽ>ᑨÆ&টiCjCEA.AO,ᚖ£JE¿ÀMDC^AAEC,uvÄÀACᚖ `ᑖDE,9ᑮTEᐵkAC=ªᓽ>ᑨÆ.ூF"জZAOC=120°,..NC4O=ZACO=30CDTᙊOᑗADVCD,.-.ZOCD=90°,AD/ICO,.•.ZACD=60°,NC4D=30°,:.CD=-AC,iOjOE_LAC,ᚖ£JE,2ᑣCE=AE=AC=C£,2^\OE=-OC=-r,NOCAwNCOE,:.CE^OE,22:.CD^-r,ᦑজ┯Ë&2
74DঝA4OCJ¨,ZAOC=ZOAC=60°,AC=OC=OA=r,.•.NGWE=30..OE=—AO,AE=—AO=—r,222iAj/1E_LOC,ᚖ£JE,.• Ç<AECDJÈঞῪAOCḄ=ª«¬i,:.AD=CD,vZADC=90/.ADAC=ZDCA=45°,ÌNOCD=90°,/.ZACO=ZCAO=45°:.ZDAO=(X)°,Ç<AOCDJÈ,.-.CD=AO=r,ᦑঞ¨·;
75টiCjCELAO,ᚖ£JE,OCLCD,ADA-CD,:.OC//AD,.\ZCAD=ZACO,OC=OA,. .ZAOC=ZCAO,:.ZCAD=ZCAO,/.CD=CEᙠAAZX?TAAEC5ZD=ZA£C,CD=CE,AC=AC,/.MDC=&\EC(HL),.AD=AE9ACᚖ `ᑖÎᑣTEᐵk4c=ª,Ï´$µᙠ ᦑট¨·.ᦑ¨·Ḅ¸¹J"ঝঞট,
76ᦑFᫀJ"ঝঞট.ூLM⚪ὃPQᢚ³Ḅឋ.<Ḅឋ.ῪḄឋ.`a Ḅឋ.ᑗ Ḅឋ.ᚖ $ᳮUVÐÑÑJ´Òឋ.$ᳮ⚪Ó⌕⌲´ᑖ᪆ᑭᵨឋ.$ᳮÖa/×.2. 2020ØÙT15,3ᑖᙠ6x6ḄÚÛÜ5ÝÞÎÚÛß/×tAACBJῪ mnOC,9tN8OC=90,rstOBḄã0ᑭᵨäå8tBCḄQ.ூF"ÝÞÎÚÛß77ᦑFᫀJ"—2ூLM⚪ὃPQḄnᙊwáḄrsz,ᙊᕜ$ᳮ⚪ᐵᑭᵨ<èi^_$ᳮ⌮$ᳮ9tA4cBJῪ .ஹF⚪1. 2020•ᑁℳëèìT22,7ᑖOḄ 43í]î CDkP,~PC2=P3B4,8¿"ABrCD.ூὃM5 ᙊᕜ$ᳮ&S9"ïḄᑨ$wឋ.ூ(⚪67"/ᳮ01&55"Ḅï&559"ᙊḄᨵᐵᭆ+,ឋ.ூᑖ᪆mnACஹBC,᪷;ᙊᕜ$ᳮ9ᑮ44=N£>,ZC=ZB,ᑣ>ᑨÆAAPC^ABPD,ᑭᵨïð9ᑮᑭᵨPC=P8ñA9ᑮ=ᯠó᪷;ᚖ $ᳮ9ᑮ.ூF¿À"mnACஹBC,ZA=NO,NC=NB, .MPCsgPD,:.PC:PB=PA:PD,;.PCPD=PAPB,PC2=PBPA,:.PC=PD,4?J ,\AB±CD.
78ூLM⚪ὃPQïḄᑨ$wឋ."ᙠᑨ$ÞïÓWôõᑭᵨ5\ᨵḄäᐳஹäᐳ<◚ºᩩøzᐙᑖúᢵüMḄjᵨýþïḄ´ÿ ᪀⌼ᮣᵨḄឋ⊤ Ḅᐵ ὃ"rᙊᕜ&ᳮ(ᚖ*&ᳮ.2..202001234T22,8ᑖ9;<=ᙊAOBḄA*C=ᙊCḄDEADᑖNS4cJ=ᙊKED,EZW_LACQACḄRSJKEH..19UVW”=ᙊḄᑗ .29Z”=2\sinZBAC=—,U=ᙊḄA*.3ூὃEM5 ᙊᕜ&ᳮ T7WeA M2 ᚖ*&ᳮ KQ fg&ᳮ ME ᑗḄᑨ&Qឋ KF ᑖḄឋூi⚪67Wlᳮmn 554WQᙊᨵᐵḄqrᐵ ூᑖ᪆.19tu8,᪷wxῪḄឋzᑮND4O=NAO,᪷wᑖḄ&~zᑮNC4D=NQ4Q,xᣚzᑮ=,UzAH//QD,᪷wḄឋzᑮOD1DH,Kzᑮ .29tuJ□KE,᪷wᙊᕜ&ᳮzᑮNACB=90l0CEDzᑮCE=O"=20ZDEC=90°,᪷wᦪḄ&~ᓽzᑮ.ூe.19VWtu.%>OA=OD,ZDAO=ZADO,A£>ᑖZBAC,ZCAD=ZOAD,:.ZCAD=ZADO,:.AH//OD,DH±AC,:.OD±DH,
79=ᙊḄᑗ (2)eWtu8cJODKE,A3=ᙊ498ḄA*ZACB=90°,.• 0CEZ»/:.CE=DH=2f,ZDEC=90°,.-.ODYBC,BC=2CE=45/5,.BCfsinN8AC==—,AB3:.AB=\2,ᓽ=ᙊḄA*12.ூE⚪ὃ"ᑗḄᑨ&xῪḄឋᑖḄ&~Ḅᑨ&ᚖ*&ᳮ᪀¡A(e⚪Ḅᐵ¢.3.(202001234T27,10ᑖ);OḄ=*R,ᐸᑁu┦A8C§ஹZBஹNCᡠªḄᑖ«ஹbஹc.(1)UVW==sinZAsin/BsinZC(2)ZNA=60NC=458c=46ᑭᵨ(1)ḄUA3ḄS(sinN8Ḅ.ூὃEM5 ᙊᕜ&ᳮ MA ḄuᙊQ¯ T7WeAூi⚪66W°mn 559WᙊḄᨵᐵᭆ²³ឋூᑖ᪆পVWA*BE,tuCE,;ᡠWᑣN8CE=9ONE=/4,᪷w
80ᦪḄ&~zᑮsinA=sinE=0^=2,Uz=2R,·ᳮWg^=2R,BE2RsinAsi¸8—=2R,Kzᑮ;sinZC46x*4c(2)ᵫ(1)zW-^-=—z¾|JA3=——T=-^-=4>/2,2Á=*=8,Â3_LACsinCsinABB2TKeAzᑮAC=AH+C”=2.⊈+ᢣ9᪷wᦪḄ&~ᓽzᑮ.ூe.19VWA*8E,tuCE,;ᡠ:ᑣZBCE=90°,Z£=N4,.■,sinA=sin£=—=—BE2R-^—=2R,sinA—^—=2/?,·ᳮ:ᓰ2RsinZBab—=2R sinZAsinZ.BsinZCABBC(2)e:ᵫ.19z:—fsinCsinA=2R,sin45°sin60°4hi\DAB=——=472,2.i\———o,GÌ~2T3KZAHB=ZBHC=900,AH=/Aficos60°=472x-=2-j2,CH=—BC=2^6,22AC=AH+CH=2(0+Ï4~~
81ூE⚪ὃ"Ḅuᙊஹᙊᕜ&ᳮஹᦪ&~ஹxῪAḄᑨ&Qឋஹfg&ᳮxÐÑ ÒÓÔÕᙊᕜ&ᳮ(ᦪ&~e⚪Ḅᐵ¢.ᦪ4. 202001⍒×T24,10ᑖ9;ᙠRtAABC§ZACB=90°,45CḄDEÙADA*ḄOBCE,JACKEÚECCG_LABJ¾KEG,AEH,EEḄÛEPJKE EPÜA*9EÛEPḄ§Et5ÚBPាkḄᑗ. 1UVWBCḄᑗ. 2UVWEF=ED. 3ZsinNA8C=2,AC=15,U0CHQEḄ☢Þ.ூὃEMR ᙊḄßᔠ⚪ூi⚪67Wlᳮmn 152Wáâßᔠ⚪ூᑖ᪆.1tuOE,OP,᪷wᚖAᑖḄឋzᑮ/ã=ẑ᪷wᐰxḄឋzᑮZBEO=ZBPO,᪷wᑗḄᑨ&(ឋ&ᳮᓽzᑮ..2᪷w(xῪḄឋᓽzᑮ. 3᪷wᚖ*&ᳮzᑮ᪷w(xῪḄឋzᑮNC4E=NE4O,᪷wᐰxḄឋzᑮCE=QE,l0C”QEæeAzᑮCG=qAClAG2=12,᪷wfg&ᳮᓽzᑮ.ூe.1VWtuOE,OP,PELAB,EQÛEPḄ§E,.• /3ᚖAᑖṺ..PB=BE,
82OE=OP,OB=OB,:.ABEO=ABPO(SSS),:.ZBEO=ZBPO.BPḄᑗ:.ZBPO=90,/.ZBEO=90°L:.OEmBC,.•.BCOḄᑗ.(2)eWZBEO=ZACB=90°,:.AC//OEfZCAE=ZOEAfOA=OE,ZEAO=ZAEO,ZCAE=ZEAO,EF=ED.(3)eWAOḄOA*EQÛṺḄ§E,:.EPLAB,CGA.AB,:.CGEP,ZACB=ZBEO=90°, •.ACHOE..\ZCAE=ZAEO,OA=OE,ZEAQ=ZAEO,ZCAE=ZEAO,ZACE=ZAQE=90°,AE=AE,/.AACE=AA(2E(A4S),/.CE=QELZAEC+ZC4E=NEAQ+ZAHG=90°L
83:.NCEH=ZAHG,ZAHG=/CHE,/.ZCHE=ZCEH,:.CH=CE,CH=EQ,/.0CHQE0CH=CE,0CHQEæ4G3sinZABC=sinZACG=——=-,AC5AC=15,AG=9,CG=>JAC2-AG2=12,AACE=AAQE,AQ=AC=15,QG=6LHQ2=HG2+QG2,HQ2=(12-"0)2+6?,ezWHQ=^-,.CH=HQ=-^,0C”QEḄ☢Þ=C4GQ=yx6=45.ூE⚪ὃ"ᙊḄßᔠ⚪ᑗḄᑨ&(ឋᐰxḄᑨ&(ឋfg&ᳮ,
84æḄᑨ&(ឋᚖ*&ᳮèéḄe⚪Ḅᐵ¢.5. 2020êëì3íîï4ðñT22,8ᑖ9;1,ᙠ0A8CD§AD//BC,/D4B=90ABḄA*COᑖ/BCD. 1UVWACDQᑗ 2;2,ò.1§ḄᑗEE,PóôAECDEAD=\,BC=2.Utan/APEḄ.;1;2ூὃELIWAõ M5Wᙊᕜ&ᳮ MEWᑗḄᑨ&Qឋ T7WeA.ூi⚪553W;Ḅᐰx 557Wõ 559WᙊḄᨵᐵᭆ²³ឋ 55AWQᙊᨵᐵḄqrᐵ 6Wmnö÷.ூᑖ᪆.1VWOEJ_CZKE,VøOCEgAOCB A4S,zOE=OB,ᓽz 2ùLBCKF,tuBE,ᑣ0ABFDWAB=DF,BF=AD=1,ᑣCF=1,VAOஹBCḄᑗᵫᑗS&ᳮzE£>=AO=1,EC=BC=2,ᑣCD=ED+EC=3,ᵫfg&ᳮznÚ=2úûU08=0,Vᵫᙊᕜ&ᳮzNAPE=NABE,ᑣN4PE=NBC”ᵫᦪ&~ᓽzᫀ.ூe.1VWOELCOKE,;1ᡠWᑣNOEC=90' AD//BC,ND4B=90.".ZOBC=180°-N£>AB=90°,ZOEC=ZOBC,ADWCOᑖNBC/|ஹJ.ZOCE^ZOCB,ok"K;1
85ZOEC=NOBC,ᙠAOCE(AOCB§■ZOCE=NOCB,,OC=OC,:.oOCE9XOCB(A4S),OE=OBLýWOEA.CD,þACOQᑗ (2)eWùLBCKÚtuBE,;ᡠ2Wᑣ0A8FD.AB=DF,BF=AD=l,.CF=BC-BF=2-1=1,'AD//BC,ND4B=90.ADLAB,BC1AB,.AD,BCḄᑗᵫ(1)zWCOOḄᑗ.ED=AD=\,EC=BC=2,.CD=ED+EC^3,.DF=VCZ^-CF2=732-l2-2V2,.AB=DF=2y/2,.OB=y/2,WCOᑖ/BCD,]COLBE,.NBCH+NCBH=NCBH+NABE=90°,.NABE=ZBCH,,/NAPE=ZABE,.NAPE=NBCH,OBV2/.tanZAPE=t3LnZBCH==.BC2ூE⚪ὃ"ᑗḄᑨ&QឋஹᐰxḄᑨ&QឋஹAõḄឋஹ
86fg&ᳮஹᙊᕜ&ᳮxÐÑ ÒÓÔÕᑗḄᑨ&Qឋ(ᙊᕜ&ᳮe⚪Ḅᐵ¢.6. 2020ÿᓅᜩT21,8ᑖᙠAABCAB=AC,ABḄOBCḄACA3ḄpNBAC=2NBDE. 1 DFOḄᑗ 2 Cb=2, =3!AFḄ.ூὃS9 &'()*Ḅᑨ,-ឋ/ Ὶ ᑗḄᑨ,-ឋ/ KH1Ὺ()*Ḅឋ/ M5 ᙊᕜ),ᳮூ6⚪67 8ᳮ9: 55C -ᙊᨵᐵḄ=>ூᑖ᪆@1ABD,AD,᪷DᑗḄᑨ,ᓽF.@2ᐜHAEOIAE4bJ0=%,᪷D&'()*Ḅឋ/ᑡOᐵxḄPQRSFOTᫀ.ூVTV @1ABD,AD,WX/.ZADB=90°,ADLBC,AB=AC,;.ZBAC=2ZBAD,/BAC=2/BDE,.•.ZBDE=NBAD,OA=OD,.•.ZBAD=ZADO,ZADO+ZODB=90°,:.ZBDE+ZODB=90°,.\ZODE=90°,
87ᓽDFLOD,8XOḄZ:.DFLOḄᑗ.(2)AB=AC,ADYBC,/.BD=CD,BO=AO,:.ODIIAC,..^EOD^AEAF9OD_EO…S\]‘JOD=xLC=2,BE=3,. .OA=OB=X,AF=AC-CF=2X-29EO=x+39EA=2x+3,xx+3-------=--------,2x-22x+3V_x=6,`abx=6XᑖcPQḄV,/.AF=2x—2=10.ூde⚪ὃf&ᙊḄgᔠi⚪jkᑗḄᑨ,&'()*Ḅឋ/-ᑨ,VPQ1lm◤⌕pqᮣstᵨᡠplm.7. 2020wᓅxy,T21,8ᑖᙠz{*A8cADUBC,AB=2^a,ZABC=60,8ḄO-{Ḅ3cᑖ|E,}.OGL3C,ᚖG,OG=a.AB03,OE,OF.
88D(2)qBE=BF, O-AD&ᑗA.ூὃM2 ᚖ,ᳮ KQ-.,ᳮ MD-.ᑗḄᑨ,ூ6⚪67 8ᳮ9: 55A -ᙊᨵᐵḄᐵூᑖ᪆(1)ᳮᵫᚖ,ᳮ_ᑮ8G=FG=a,ᑣᒼ,ᡭG=OG,ᡠABOGAOFGX1Ὺ)()*ᑣN3OF=90RSFᑨABOF1Ὺ)()*.(2)ABᔊᐜHABEF1{()*H£ஹஹGᐳᓽEG_L3F,BḼ=>O85=286=2=48,ᑣFᑨA-EᔠᯠHAGA£),RS_ᑮ-4)&ᑗA.ூVT(1)V 1Ὺ)()*.ᳮᵫ OGLBC,.-.BG=FG=-BF=a,2OG=a..BG=OG,FG=OG,:.\BOGGX1Ὺ)()*:.ZBOG=ZFOG=45°,;.ZBOF=90°,S8=OF,.•.MOᔆ1Ὺ)()*.(2)H ABEZEBF=60BF=BE,..ABEFYstuv, .EB=EF,OGᚖᑖᡂ,
89..£ஹOஹGᐳ,ᓽEGA.BF,OG=a,NOBG=30°,BG=y/3OG=,:.BE=2BG=2>/3a,SAB=,.•.A-EᔠAD//BC,AG1BF,AGYAD,-AZ&ᑗAADB\~G/FCூde⚪ὃfᑗḄᑨ,,ᳮ `ZḄ¢£ᚖ¤ᩩZḄXᙊḄᑗ.¦ὃf1{()*Ḅᑨ,-ឋ/ᚖ,ᳮ.8.(2020wᓅ§¨T21,8ᑖ)ᙠHAA3CZABC=90°,ABḄOACO,AE-Ḅᑗ©&ᚖᚖE.(1) 49ᑖNS4E (2)qCD=DE,sin44cḄª.ூὃMC-.ᑗḄឋ/ M2 ᚖ,ᳮ 77 V)()* M5 ᙊᕜ),ᳮூ6⚪64 «¬ 55A -ᙊᨵᐵḄᐵூᑖ᪆(1)AB8,᪷DᑗḄឋ/_ᑮᑣFᑨ8//A£,RS
90_ᑮN1=NOZM,ᯠᑭᵨN2=N84_ᑮ4=N2 (2)ABᓽᑭᵨᙊᕜ),ᳮ_ᑮN4ZM=90HN2=N3,ᑭᵨ()¯ᦪḄ,±_ᑮsin4=ᓛsinZ3=—,ᑣAD=BC,JCO=x,BC=AD=y,HADBCACD^ACBhᑭᵨ&'³_ᑮx:y=y:(x+y),ᯠO/ஹyḄᐵF_ᑮsinNBACḄª.ூVT(1)H AB8,DEᑗw,..ODLDE,DE]AE,:.OD//AE,:.ZX=^ODA,OA=OD,.\Z2=ZODA, Z1=N2, .ADᑖNa4E (2)V AB³),AB.\ZADB=90°,Z2+ZAB£>=90°,Z34-ZABD=90°,. .N2=Z3,,xDE.µDCADBCDE=DC,A£)=BCLJCD=xLBC=AD=y,NDCB=NBCA,Z3=Z2,/.ACDBs^CBAL:.CD:CB=CB:CA,RPx:y=y:(x+y),ᳮ_f+U+y=O,V_·¸(¹yᡈx=(»¼)
91ᓽsinNBACḄª@¸!■ூde⚪ὃfᑗḄឋ/ ᙊḄᑗᚖ`ᑗḄZ.ÇOÈᙊḄᑗÉAᑗḄZ᪀⌼,ᳮ_Oᚖᐵ.¦ὃfᙊᕜ),ᳮV)()*.9.@2020wᓅ឵ÐÑT23,10ᑖ1,•XOḄA”-&ᑗA,BN-&ᑗ3,C@×AᙠAA7ÙᙠÙ£8=C4,CDBN&E!ABADÛBNF.@1 CEḄᑗ @2 BE=EF.@32,ABEOÛ-ᑖ|&GஹH,ABBH.ÇAB=6,AC=4,tanNBHE.ூὃMR ᙊḄgᔠ⚪ூ6⚪69 àᵨám 152 «¬gᔠ⚪ 559 ᙊḄᨵᐵᭆäkឋ/ூᑖ᪆@1AB8᪷D1{å1)Fl ZCAD=ZCDA,ZOAD=ZODA,᪷DᑗḄឋ/FlNC40=NC4£>+NQ40=N84+NQ1M=90o=NaX:,ᵫᑗḄᑨ,,ᳮF_îï @2AB8D,᪷D1{å1)FlNODB=NOBD,᪷DᑗḄឋ/Fl
92NODE=NOBE=90,ᵫ1ñò1ñó&1_NED8=2ô£),᪷D1)å1{_ᑮED=EB,ᯠ᪷DõḄឋ/kå⚔)&1F_NED^=NETO,8O£¸ᡠᵫ÷_Oîï (3)øᒹ4ú£,᪷D,ᳮFO3ḄᓽFOtanNHOEḄªᑭᵨû)ücᓽFOtanNOýḄª.ூVTV (1)1ABOD,8=6.\XCAD=ZCDA,OA=OD. .Z.OAD=Z.ODA,AM-&ᑗA,/.ZCAO=ZC4D+ZOAD=90°L/.ZODC=ZCDA+ZODA=90°L.•.CEOḄᑗ.(2)2ABþ),OD=OB,. .NODB=NOBD,CEḄᑗBFḄᑗ/.Z.OBD=AODE=90°L:.yDB=AEBD,ED=EB,AMLAB,BNLAB,:.AM//BN,:.Z.CAD=ZBFDL4CAD=/CDA=AEDF,.ZBFD=ZEDF, .EF=ED,.BE=EF.
93(3)2øᒹ_LAMᑣABEL,23E=x,ᑣd=4-x,CE=4+x,(4+x)2=(4-x)2+62,9 X"9tanZBOE=—=^=-0834ZBOE=2ZBHE,2tanNBHE3tanZB0£=------------=-,1-tan2ZBHE4 tan/BHE1ᡈ-3(-33ᔠ⚪678),tanZ.BHE=-.3⊡ᐙ;<2>?@£3A£»ḄDEF/.RF3tabABOE=-=-,OB4 '.IJᎷL=34OB=4k,ᑣOE=5NOB//HJ,生心0EEB以OPOQ一5k3k99kEJw36,…27,=—k,EJ=Pk,552712:.BJ=EJ-BE=—k—3k=—k55BJI/.tanZ.BHJ=H7~34BHE=NOBE=4BHJL
941ூWXZ⚪[⌕ὃ^_ᑗFḄᑨbcឋefῪhiḄᑨbcឋejkFḄᑨbcឋehilᦪ/,nobᳮfqrstuvwxqrWyzst{ᵨ ⚪Ḅᐵ~.10. 2020ᓅᑄT21,7ᑖqA5OḄWEOOWWZAEOWyDEWC,NCBE=ZBDE,BDAEஹF. 1BCḄᑗF- 2jᑖNAfiE,AD2=DFDB.ூὃWME ᑗFḄᑨbឋe-M5.ᙊᕜibᳮ-S9hiḄᑨbឋeூ⚪55AᙊᨵᐵḄᐵ-67ᳮzூᑖ᪆1᪷¡ᙊᕜibᳮᓽI £ZEAB+ZEBA=9G°,¤ᵫ¦q £ZABE+NCBE=90°,ᑣC8_LA8,§¨ OḄᑗF- 2©ª AADPsMDA, £hiḄ«{ᡂ®ᓽI ¯°.ூ ±²1³OḄ:.ZAEB=90°,:.NEAB+NEBA=90,ZCBE=ZBDE,ZBDE=ZEAB,:.Z£AB=ACBE,:.ZEBA+ZCBE=90°,ᓽZABC=90°,
95:.CBA.AB,ABOḄ:.BCOḄᑗF-(2)²BD[ᑖZABE,.-.ZABD=ZDBE,ZDAF^ZDBE,:.ZDAF=ZABD,ZADB=ZADF,.'./SADF^ABDA,.AD_DF~BD~7J5' .ADr=DFDB.ூWXZ⚪ὃ^_ᑗFḄᑨbhiḄᑨbcឋe-⌕´FᙊḄᑗF¦qµFªᙊ´Wᙊ¶wW(ᓽ·)¤ᚖᓽI.II.(2020•º»¼ᜮT22,8ᑖ)1,ᙠA8CQ>AD//BC,ZDAB=90°,AB0ḄCOjᑖN2CD.(1)FCQ0ᑗ-(2)2,Ä(1)>ḄᑗWE,ÅÆÇAFOWAD=1,BC=2.tanNAPEḄÊ.ூὃWLIiË-M5ᙊᕜibᳮ-MEᑗFḄᑨbឋe-T7 ihi.ூ⚪553Ḅᐰf-557Ë-559ᙊḄᨵᐵᭆÎÏឋe-55AᙊᨵᐵḄᐵ-6zÐÑ.ூᑖ᪆(1)²?OELLCDE,ÒOCEÓÒOCB(A4S), £OE=OB,ᓽI
96 £¯°-(2)?F_L8CF,8E,ᑣA8RDAB=DF,8F=A£×=1,ᑣCP=1,Aஹ8cḄᑗFᵫᑗFEbᳮ EQ=AQ=1,EC=BC=2,ᑣCD=ED+EC=3,ᵫnobᳮ Å=2&,ᑣ8=ÛzNABE=NBCH,ᵫᙊᕜibᳮ NAPE=NABE,ᑣN4PE=NBC”ᵫhilᦪbÝᓽI £±ᫀ.ூ ±(1)²?EJ_COE,1ᡠáᑣNOEC=90°,'."AD//BC,NZMB=90°,/OBC=180°-ND4B=90°,.ZOEC=ZOBC,-Cjᑖ/BCD,.NOCE=NOCB,ZOEC=NOBCᙠÒOCEcAOCB>}ZOCE=NOCB,OC=OC...ÒOCEdOCB(A45),OE=OB,ãOE_LC£),FC£×0ᑗ(2) ?OF_LBCäBE,ᡠáᑣA8F.AB=DF,BF=AD^\,.CF=BC-BF=2-1=1,"."AD//BC,NDAB=90°,.ADLAB,BC1,AB,.AD.BCOOḄᑗF,ᵫ(1) CD0ḄᑗF.ED=AD=\,EC=BC=2,.CD=ED+EC=3,
97DF=yjclf-CF2=V32-l2=2å,.AB=DF=2y/2,0B=V2,COjᑖNBCCOLBE,.NBCH+NCBH=ZCBH+ZABE=90°,ZABE=ZBCH,ZAPE=ZABE,.NAPE=NBCH,ூWXZ⚪ὃ^_ᑗFḄᑨbឋeஹᐰfhiḄᑨbឋeஹiËḄឋeஹnobᳮஹᙊᕜibᳮfqr-stuvᑗFḄᑨbឋecᙊᕜibᳮ ⚪Ḅᐵ~.12. 2020•º»æᙥ201,8ᑖABOḄWCᙠ4ªWCḄᑗFèᚖᚖéO.3CyDEA4ḄDEFWE.1AE=AB (2)AB=10,BC=6,CE>ḄE.
98EூὃWXXhi>Fbᳮ-MCᑗFḄឋeூ⚪55AᙊᨵᐵḄᐵ-64êëìூᑖ᪆(1)²ACஹOC,᪷¡ᑗFḄឋe IOCVCD,ᑣIᑨíOCUAD,ᡠJ=ᯠÛ²NB=4,§¨ ᑮ¯°-(2)ᑭᵨᙊᕜibᳮ ᑮNACB=90ᑣᑭᵨnobᳮIñò£AC=8,¤᪷¡fῪhiḄឋe ᑮCó=8=6,ᯠÛᑭᵨ☢õ<£CDḄE.ூ ±(1)²ACஹOC,8ᑗFJ.OCLCD,s.CDLAD,:.OC//AD,ZOCB=ZE,OB=OC,,/OCB=/B,:.ZB=ZEfAE=AB-(2) AB/.ZAC^=90°,z.AC=V102-62=8,AB=AE=]O,AC-LBE,/.CE=BC=6,-CDAE=-ACCEf22
996x8_24ூWXZ⚪ὃ^_ᑗFḄឋeᙊḄᑗFᚖöªᑗWḄ·-£÷ᙊḄᑗFøªᑗWḄ·᪀⌼bᳮ £ᚖᐵ.ûὃ^_ᙊᕜibᳮ.13.(2020•üýþT25,12ᑖ)ÒABCḄ ᙊABPO▬=PC=J5A8, ACQ,PF.(1) AF=CF.(2)"tan/ABC=2&, )*Ḅᑗ-.(3)ᙠ(2)ᩩ23 PBE, OE,"BC=2,6OEḄ.ூᑖ᪆(1)✌ᐜ =ᚖ?@ᑖ-A4C,ᑭᵨᚖEFᳮHIJK.(2)LBC=mNOPQ 42=RS£),UVWAOPSOOAᓽHYZ[⚪.(3)^OE_=J,BKPFK.`ab6VEJ,D/ᓽHYZ[⚪.ூYd(1) OC.\'PC=PA,OC=OA,eᚖ?@ᑖ-AAC,:.AF=CF.
100(2) LAB*?E\ZACB=90°,ACrr•*tan^,ABC==2>/2,BC,.AC=2V2a,AB—VBC2+AC2—1/a2+(2V2a)2)—3a,•.OC=OA=OB=ḄCD=AD=6a,2:PA=PC=6AB,L.PA=PC=3ba,ZPDC=90°,,•PD=~PC-CD=V18a2-2fl2=4DC=DA,AO=OB,II OD=-BC=-a,22\AD1=PD-ODf.AD_OP•g⁰’ •NAOP=NADO=90 /XADPsl\ODA,\ZPAD=ZDOA,ZDOA+ZDAO=90°,\ZPAD+ZDAO=90% /%=90\OALPA,••k*Ḅᑗ-.(3)Y^OE_E/_LPbJ,BKLPFK.BC=2fᵫ(I)HmPA=6y/2,AB=6,
101,ZPAB=90°,.PB=yJP^+AB2=J72+36=6n *=PE-PB,72.PE—4\/3,65/3,/ZCDK=NBKD=ZBCD=90°,opqCZ)KB*tq.CD=BK=2i,BC=DK=2,,:PD=8,.PK=10,"JEJ//BK,•PEEJ_PJ"'~PB~~BK~~PK'•6#>_EJ_PJ,,4g2V210).45/220.EJ=------,PJ=—,33ூuv⚪wᙊxᔠ⚪ὃ{|ᚖEFᳮᑗ-ḄᑨFY?~~q~qḄᑨFឋmY⚪Ḅᐵ*ᑭᵨᦪYZ[⚪wὃ⚪.14.2020•┱,T1,8ᑖ^OOḄᙊOAஹ3,DC*OḄᑗ-,C*ᑗmNO=30DC=6(1)6 MiOCsgCD
102 26ABC£Ḅᕜ.ூὃM5 ᙊᕜ~Fᳮ.S9~qḄᑨFឋ.MCtᑗ-Ḅឋூ⚪55AᙊᨵᐵḄᐵ.554Ὺ~q?~~q.559ᙊḄᨵᐵᭆ£¤ឋ.55D ^qḄ.67Uᳮ¥¦ூᑖ᪆1ᵫᑗ-ḄឋHINO8=90ᵫ~ḄឋHIN8OC=120ᵫῪ~qḄឋZB=NOCB=30HINB=ND=30ZDCB=120=NBOC,HIJK.2ᵫ?~~qḄឋHIOC=1=O3,00=2,ᓽH6Y.ூYd 10c*Ḅᑗ-.-.ZOCD=90°,Z£>=30°,/.ZBOC=ZD+ZOCD=30+90=120°,OB=OC,:.ZB=ZOCB=3Q°,ZDCB=120°=ZBOC,¨ZB=NO=30°, 2"=30DC=>fi,ZOCD=90°,DC=y/3OC=s/3,DO=2OC, .OC=\=OB,£>0=2,ZB=ZD=30°,DC=BC—n,r.ABCḄᕜ=8+3C+08=6+6+2+1=3+2n.ூuv⚪ὃ{|~qḄᑨFឋᑗ-Ḅឋ?~~qḄឋᮣª«ᵨ¬ឋ®¯Uᳮ*v⚪Ḅᐵ.
10315. 2020•°±,Tl,10ᑖ^AABCᑁ O,ZB=60°,£ᙠ?EC£Ḅ-³A£=AC. 1´ᑨµAEOḄᐵ¶· ᳮᵫ;2"AC=6,6▢º»ᑖḄ☢½.ூὃM5ᙊᕜ~Fᳮ.MB?-ᙊḄᐵ.MOᡧq☢½ḄPQ.MA~qḄ ᙊூ⚪55AᙊᨵᐵḄᐵ.64¿À?Áூᑖ᪆1 4ஹAD,H6INACE=NAEC=3OH A48Âp~qH6INE4O=90H AEÂOḄᑗ-. 2_OFJ_ACFJᔠ1HIᑮOA=2GAE=6,Ä᪷ÆᙊḄ☢½ÇÈᡧq☢½ÇÈᓽH6Y.ூYd1 4ஹAD,^CDOḄ?E/.ZZMC=90°,¨ZADC=ZB=60°,:.ZACD=30P,¨AE=AC,OA=OD,.•.A4DOÂp~q.-.ZE=30o,ZADO=ZDAO=C^6°,.\ZPAD=30°,:.ZEAD+ZDAO=90°,:.OALE,ÉÂḄᑗ-. 2Y_Ok_LAC
104ᵫ(1)HmAAEOÂ?~~qNE=30OA=26,AE=6!▢º»ᑖḄ☢½Â-x6x2x/3-6ᐔxQ=2Í2360ᦑ▢º»ᑖḄ☢½Â66-2%.ூuv⚪Ï⌕ὃ{ᑗ-ḄᑨFឋÑÒᑗ-Ḅ Ób*Y⚪ḄᐵᓽᨵᑗÔ ᙊᑗ ᚖ?ÕᨵᑗÔ_ᚖ? Ö×ØE.ÙÚ¬Û[⚪ḄÜᵨÝÞ-Ḅ_b.1.(2020ßàáT26,10ᑖ)âm*AAfiCḄ ᙊADÂḄ?EAO_L8C,ᚖçÂE, 80,30AC.(1)^1,6 ZBFC=3NCAD.(2)^2,O_£>G8OG,HÂGḄ O4,6 :BE=OH.(3)^3,ᙠ(2)Ḅᩩ23 CG,"AGHE,A4OᔆḄ☢½ÂØ6-ACGூὃMR-.ᙊḄxᔠ⚪ூ⚪553^qḄᐰ.559ᙊḄᨵᐵᭆ£¤ឋ.67Uᳮ¥¦.550^qḄ
105.554Ὺ~q?~~qூᑖ᪆(1)ᵫᚖEFᳮHIBE=EC,ᵫ-Aᚖ?@ᑖ-ḄឋHIñ=AC,ᵫῪ~qḄឋHIABAD=ZABO=ACAD,ᵫ~ḄឋHIJK.(2)ᵫ“A4S”H ò50£.=40£>HI=(3)O/_,.ADN,LZ)G=£>E=2x,ᵫᐰ~qḄឋHIOE=DH=x,OD=3x=OA=OB,óôFᳮH6BE=2õᵫ┦~~÷ᦪH6AN=QNF,ON=—NF,AO=AN+ON=£^~NF,ᵫ~q☢½ÇÈH6NḄ44H6x=l,BE=2=OH,AE=4,DG=DE=2,óôFᳮH6AC=2«, AG,OA_AW_LCG,GCḄ-M,NO AACMsAADG,ᵫ~qḄឋH6AM,C/0ḄᵫóôFᳮH6GMḄᓽH6Y.ூYd (I)ADOḄ?EAD±BC,BE=EC,AB=AC,¨AD1.BC,:.ZBAD=ZCAD,OA=OB, .ZBAD=ZABO,. .ABAD=ZABO=ACAD,ZBFC=ZBAC+ZABO,:,ZBFC=ZBAD-^ZEAD+ZABO=3ZCAD (2)^2, AG,D^24)*?E,ZAG=90°,*0G,
106:.DH=HG,¨AO=DO,OH//AG,AG=2OH,/.ZAGD=ZOHD=90°LDG//BF,:"BOE=NODH,¨/OEB=/OHD=9QP,BO=DO,:.\BOE=\ODH{AAS),:.BE=OH (3)^3,O/_FNJ_AD,ADN,LDG=DE=2x,:.DH=HG=x,NBOEwMODH,:.OE=DH=x,/.OD=3x=OA=OB9BE=\IOB2-OE2=x1=2ঝ,ZBAE=NCAE,BENF...tanZBAE=tanZC4E=—=—,AEAN2y/2xNF----=---4xANAN=bNF,/BOE=ANOF,tanZ/.BMOLE-tanù/NrOCLF=B-E---=N--F---,OEON.2û_NF-x~~ONf
107,ON=—NF:f4sO:.AO=AN+ON=^—NFf4AAOᔆḄ☢½Âü5-xAOxNF=NF?=2245...NF=ý55BAO=LNF=3=3x,4x=1,:.BE=2⊈=OH,AE=4,DG=DE=2,AC=y/AE2+CE2=716+8=276,^3, AG,OA_AJ_CG,GCḄ-M,ᵫ2HmAG=2OH=45/2,opq/WGC*ᙊᑁ opq/.ZACM=ZADG,¨ZAMC=ZAGD=90°,.-.AACM^AADG,.ADAGDG"AC~AM~CM'.6402"ÿ ’•r,276“8y/34..CM=-----AA/=------33:.GM=4AG1-AM1=J32-y=,
1082%:.CG=GM-CM=^—.3ூ⚪ᙊḄᔠ⚪ὃᙊḄᨵᐵ ᐰ !Ḅᑨ#$ឋ& !'()#ᳮ+, !Ḅᑨ#$ឋ&┦ .ᦪ 01N2Ḅ3⚪Ḅᐵ4.1.1. 7ᑖ7 2020•9:7<OḄ=>AB?@AB=>78CP,DE20GHABYCD.ூὃM5Hᙊᕜ#ᳮJ59H+, !Ḅᑨ#Kឋ&ூL⚪67HMᳮNOJ55H#ᳮZᑮgh.ூijGkHUVACஹBC,<ZA=Z£>,NC=/B,MPC^/^PD, .PC:PB=PA:PD,:.PCPD=PAPB,PC2=PBPA,:.PC=PD,A3l=>:.ABYCD.
109ூ⚪ὃ+, !Ḅᑨ#Kឋ&Hᙠᑨ#no !+,pqrsᑭᵨ#ᳮ.2.L(2020T22,10ᑖ)<C,DOnDᙠ=>nUg8?CE,GAC ZA£)C=ZG.(1)0GHZ1=Z2.(2)CᐵCDGḄ¨©lF,UgCF.ªF«ᙠ=>ABpCᡝ=10,tanN1=—,50Ḅ³>.ூὃT7Hi= !JP2 µ¨©Ḅឋ&JM5 ᙊᕜ#ᳮூL⚪66H·NOJ14HGk⚪J67HMᳮNOJ55CHKᙊᨵᐵḄ¸·ூᑖ᪆(1)᪷Yᙊᕜ#ᳮ$¹lḄ=>ᓽ]GkN1=N2J(2)UVDF,᪷Yᚖ>#ᳮ]Zಘ=FC=1O,¾᪷Y¨©ឋ]ZDC2¿]ZDEḄ3¾᪷Y┦ .ᦪᓽ]01OḄ³>.ூijiH(1)ZADC=ZG,AC=AD,ABOḄ=>,..BC=BD,.\Z1=Z2J
110(2)<UV2,AC=AD,ABOḄ=>:.AB±CD,CE=DE,/.FD=FC=10,C,2ᐵCOG¨©.\DC=DF=\O,:.DE=5!Ã2tanZi=—,5EB=DEtanZl=2,Z1=Z2,“2tanN2= ,5"DE25Æ.AE=-----=—tanZ2229AB=AE+EB=—,2.oḄ³>l”.4ூ⚪ὃᙊᕜ#ᳮஹµ¨©Ḅឋ&ஹi= !iÊ⚪Ḅᐵ4Ë̵¨©Ḅឋ&.2.(2020ÍT23,12ᑖ)<ᙠAABC'ZACB=90°,ÏAABCÐ=)X5ÒᢚZᑮUV8?¹CV.E)CMḄUVBE.fMOEḄVᙊK4)ḄØ o?UVᡠBF.(1)0GHSÚ= !J(2)0GHMEFSMCA (3)ªAB=6,8C=mpᙠ)CMÜᙠE,ÝZÞ$¹ß+ᑖ0àḄá.
111cᜓᵨூὃMRᙊḄᔠ⚪ூL⚪152Hâãᔠ⚪J69Hqᵨs ூᑖ᪆A1äåGkN8æ'=90ᓽ]iÊè⚪A]|ᑭᵨᙊᑁVêw!Ḅឋ&=VGk7.A2᪷Yn¨q+ n !+,Gk. 3Gkêw!AfBEtêw!M1=EF=m,ᵫAABCS&BM,22]Z—,ᵫABEJSMME,3TF,ᵫì5cA,M1=ᵫ672EFBEí᪀îï0iᓽ].ðij(1)GkHZEFB=//EDB,ZEBF=ZEDF,:.ZEFB^-ZEBF=ZEDB+ZEDF=ZADB=9(r,.\ZBEF=90°,ñ.ABE2= !.(2)GkHBC=BD,:"BDC=/BCD,ZEFB=ZEDB,:.ZEFB=ZBCD,AC=AD,BC=BD,/.AB±CE>,/.ZAMC=90°,NBCD+ZACD=ZACD+ZC4B=90°,..ZBCD=/CAB,
112:.ZBFE=NCAB,ZACB=/FEB=90,TEFs^BCA.(3)iHò£F?+CóUVᡠKôß+ᑖ■.êw!AFBöêw!•.ZEFA=4FEB=MP,ᓽṺ4%BD]AD,\EFHBD,:.AF=DF,FJgBD=U22/.EF=mMBC^ACBMLBC:MB=AB:BC,BM=—,6oBEJsMMELtnBE=ABEFSMCALACBC~EF~~BEmmiZm=26(ø᪷ùúûü).
113ூ⚪ýCᙊᔠ⚪ὃᙊᕜ#ᳮ+, !Ḅᑨ#$ឋ&êw!Ḅᑨ#$ឋ& i⚪Ḅᐵ4þÿᑭᵨᦪ᪀⚪ὃ⚪.3. 2020ᗩᐶT19,6ᑖ ᙠAaABOA=OB,O/W!ᑗ#C.$% AC=BC.&'()Ḅ%'+,᪾ %' ./OC,OA=OB,0.ZA=ZB,1oc=oc,:.OOACHAOBC,AC=BC.&'Ḅ%34ᔲ678967:ᙠ᪾ᑁᡭ“4”=9┯?:ᑏABḄ%'+.ூὃ#MCᑗEḄឋG=KD ᐰIJKLḄᑨNឋGூO⚪67PᳮRS=55AᙊᨵᐵḄWXᐵYூᑖ᪆./OC,᪷\ᑗEḄឋG]IῪJKLḄឋGᓽ`aᑮ/c.ூd %3┯?=%' ./OC,O43!ᑗ#C,
114:.OCA-AB,OA=OB,:.AC=BC.ூ#ef⚪ὃghᑗEḄឋGIῪJKLḄឋGij67ᑗEḄឋG4⚪Ḅᐵk.3.1.(2020lmT20,10ᑖ) o4pᙊOḄqrC,4pᙊtu(A,8Ḅv#AD=BC,AC8!w#x.8E4pᙊᡠᙠᙊḄᑗEACḄz{E!w#E.(1)$% XCBAt(2)qBE=BF,$% AC|ᑖூὃ#MC-.ᑗEḄឋG=M5 ᙊᕜKNᳮ=KD-.ᐰIJKLḄᑨNឋGூO⚪67 PᳮRS=55A ᙊᨵᐵḄWXᐵYூᑖ᪆(1)᪷\ᙊᕜKNᳮaᑮNACB=W3=90᪷\ᐰIJKLḄᑨNNᳮᓽ`aᑮ/c=(2)᪷\IῪJKLḄឋGaᑮNE=N8ᙠ᪷\ᑗEḄឋGaᑮZ4BE=90᪷\JKLḄᑁK]K|ᑖEḄNᓽ`aᑮ/c.ூd(1)%' /4pᙊḄqr/.ZACB=ZADB=90°,_..\BC=ADᙠRtACBARtADAB[BA=ABRtACBA=RtADAB(HL)=(2) BE=BF,ᵫ(1)8c:.ZE=ZBFE,BE4pᙊOᡠᙠᙊḄᑗE:.ZABE=90°,ZE+ZBAE=90°,ᵫ1N£>=90,
115:.^DAF+ZAFD=90°,ZAFD=ZBFE,:.ZAFD=ZE,.■.ZDAF=900-ZAFD,ZBAF=90°-ZE,..ZDAF=ZBAF,.•.AC|ᑖNZMB.ூ#ef⚪ὃghᑗEḄឋGᐰIJKLḄᑨN]ឋGᙊᕜKNᳮ67Ḅ L4⚪Ḅᐵk.2. 2020ᓅT20,5ᑖ A4BC┦KJKLAB=AC,CD//AB.$ E3P,a#PᙠqECDtSLZABP=-ZBAC.23 জ#AᙊAC{prᙊwqECDC,Pv#=ঝ.BP.E4ᡠ$ḄE. 1ᵨq]ᙊ3⊡ᐰ Lᶇ = 2ᡂ,☢Ḅ%'.%' CD//AH,:.ZABP=_ZBPC_.AB=AC,:.BᙠAt.1#C,P£ᙠAtNBPC==NBACS(¥ᡠ¦ḄᙊᕜKIᙊKḄ§p¨PᳮḄ\.:.ZABP=-ZBAC.2ூὃ#M5-.ᙊᕜKNᳮ=N3 -ªᩖ =KH IῪJKLḄឋGூO⚪64¬q®=67PᳮRS=55G =13 ⚪ூᑖ᪆ 1᪷\3ᓽ`⊡ᐰ L=
1162᪷\IῪJKLḄឋG](¥ᡠ¦ᙊᕜKIᙊKḄ§pᓽ`ᡂ,☢Ḅ%'.ூd 1 ᓽ⊡ᐰḄ L=2%' CD//AB,:.ZABP=ZBPC.AB=AC,.,.#5ᙠAt.1#C,x£ᙠAtZBPC=~ZBAC(¥ᡠ¦ḄᙊᕜKIᙊKḄ§p,2.-.ZABP=-ZBAC.ᦑdᫀ ZBPC,(¥ᡠ¦ḄᙊᕜKIᙊKḄ§p.ூ#ef⚪ὃgh -ªᩖ ஹIῪJKLḄឋGஹᙊᕜKNᳮf⚪Ḅᐵk4·ᔠ¹ᵨt.3.2020ᓅT23,6ᑖ ABḄqrC84z{Et§#CDOḄᑗEᑗ##E,w8#F.1$% ZADC=ZAOF.29sinC=LBD=8,$■Ḅ{.3ூὃ#M5 ᙊᕜKNᳮ=M2 ᚖrNᳮ=KQ ÈÉNᳮ=MC ᑗEḄឋG=T7 qKJKLூO⚪67 PᳮRS=55A ᙊᨵᐵḄWXᐵYூᑖ᪆1.8,᪷\ᙊᕜKNᳮaᑮ4£>8=90᪷\|ÎEḄឋGaᑮ
117ZAOF=ZJB,᪷\ᑗEḄឋGaᑮNCDO=90IÒÓᣚᓽ`aᑮ/c;4.2.(2020tÖT25,14ᑖ)(2020•tÖ) AABCAB=AC,ᙊ4AABCḄᙊ80Ḅz{wÚAC#O.(1)$% NBAC=2ZABD;(2)ÛABCD4IῪJKLÜ$NBCOḄᜧ&=(3)ÛAZ)=2,8=3Ü$Ú8cḄ{.ூὃ#MR ᙊḄ·ᔠ⚪ூO⚪69 àᵨá=152 ¬·ᔠ⚪ூᑖ᪆(1).4.ᑭᵨᚖrNᳮIῪJKLḄឋG⚪ᓽ`.(2)ᑖJâãL জ9=ᑣNGZG"Pt6C=é3.ঝCD=CB,ᑣNC8£>=NC/)8=3NAB£>.ঞDB=DC,ᑣAêᔠëâãLuìᙠ.ᑖᑭᵨJKLᑁK]Nᳮ᪀$ᓽ`.(3) 3AE//8CwíḄz{E£.ᑣî=î=2,PAî=ï=±,BCDC3OHBH3ñO8=Q4=4a,OH=3a,᪷\=ô4§A"?=ᱛ§,᪀$Aᓽ`⚪.ூd(1)%' .OA.1AB=AC,AB=AC,
118:.OA±BC,ZBAO=ZCAO,OA=OB,:.ZABD=ZBAO, •.ZBAC=2ZBAD.(2) 2z{AOw8.জqBD=CB,ᑣNC=ZBDC=ZAB£>+Z^4C=3ZABE>,AB=AC,ZABC=/C,:.NDBC=2ZABD,ZDBC+NC+ZBDC=180°,:.8ZABD=\80°f.•.NC=3Z/WD=67.5.ঝqCD=CB,ᑣNCBD=NCDB=3ZABD,:.ZC=4ZABDtZDBC+ZC+Z.CDB=180°,/.10ZABr>=180o,/./BCD=4ZABD=72°.ঞ9O3=OC,ᑣAêᔠëâãLuìᙠ.·tᡠøNCḄù67.5ᡈ72.(3) 3A£7/6CwḄz{Eû.
119AB 3ᑣî=ü=2BCDC3.AO-AE_4ñOB=OA=4aLOH—3clLOH--3BH2=AB2-AH2=OB2-OH2,/.25—492=162—92,.225..(1=—56.RH_54BC=2BH=—2ூ#ef⚪ᙊ·ᔠ⚪ὃghᚖrNᳮIῪJKLḄឋGqKJKL|ÎEᑖEᡂÿ ᳮ⚪Ḅᐵᵨ᪀⌼⚪ᑭᵨ ᦪ᪀ !⚪"#$ὃὃ⚪&.5.2.+2020-.,T28,10ᑖ467NMQV=90OTNMONḄᑖAABCDOA^8cm.EDPGDAHIJlon/sḄPQR49TᔣVWᒴPYEZ[\]EDGDOHI^J1cm/.vḄPQRONbcᔣBWᒴPYE.dePQ,fOT#D8.ghஹPஹjDWᙊfOT#DC,dePCஹQC.mYE]nop4,ᐸ$0120TூὃDMR-.ᙊḄᔠ⚪ூ⚪152ᔠ⚪w559ᙊḄᨵᐵᭆឋw66Y¡w67¢ᳮ¡ூᑖ᪆+1ᵫ⚪¤~HOP=8—OQ=t,ᑣ¦~H§ᫀw 26hD8Wᚖªo«+18D//OQ.m¬4Ḅox,ᑣBD=OD=j,OB=^2BD=42x,PD=8-t-x,~H=®ᑣ¯I°2=±HOPOQ8-rtx=W°².ᵫ°³´ᦪḄឋ¦~H§ᫀw8+3µAPCῪc·j·.ᑣ¸¹=32ᓽ=3*»=ᙠRtAPOQ$PQ2=0^+00^=SS-t62+t2.ᵫOPCQḄ☢S=S+S¦~AP0QAPCQH§ᫀ.ூ§+1ᵫ⚪¤¦~OP=8—f»OQ=t,OP+OQ=8-/+=8 c/n.+2¼z=4]5ḄQᨬᜧ.6hD8Wᚖªoᑣ8O//OQ.OTᑖZMON,. .ZBOD=NOBD=45°!:.BD=OD,OB=42BD.mḄox,«==OB=yf2BD=y[2xPD=8-t-x,f
121BD//OQ,PD_BD~6P~~OQ"8—t—xx••.5=¾=¿+”Á+2^.¼f=4]03ḄQᨬᜧᨬᜧ26cm.(3)NPOQ=90°,w.ÂᙊḄcÃ.ZPCg=90°.ZPQC=ZPOC=45°,w.APCQῪc·j·.11001,■S.=-PC^C=-X^-PQ^-PQ=-PQ-.AICQᙠRlAPOQ$PQ12=OP2+OQ2=(S-t)-+t2. .OPCQḄ☢S=S+S^=^OPOQ+^PQ2,AP0QQ11,,=-r(8-r)+-[(8-r)"+t2],241,1,=4r--r+-r+16-4r=16.22OPCQḄ☢oIba*.ூDÄÅ⚪ᙊḄᔠ⚪ὃÆÇᙊᕜ·ᳮῪc·j·Ḅឋᑖᡂ¯ ᳮj·Ḅ☢°³´ᦪḄឋÊËÌÍᙊḄឋᳮ⚪Ḅᐵ.3. 2020Î-Ï.,T24,10ᑖ46ᙠ$DPoABḄ$DÐ4ஹPCÑÒᚖcᚖªoM,3cᑖÓZADஹPDÒf#D£ஹN,deஹMN.+1tµNoÕ;Ḅ$D. 2Ḅ×Ão8,A8ḄQᦪo90tMNḄ.
122DூὃDKQØÙᳮூ⚪559ᙊḄᨵᐵᭆឋw67¢ᳮ¡ூᑖ᪆(1)᪷Ýᙊᕜ·ᳮ~ZADP=ZBCP,ᵫj·Ḅᑁ·ßᳮß·Ḅà~:ZDNE=NEMC=90=ZDNB,ᨬâᵫῪj·Ḅᑨßឋ¦~äåw(2)deQ4,OB,AB.AC,ᐜ᪷ÝØÙᳮ~43=8⚔èµMNḄ$é¦~MNḄ.ூ§(1)µADLPC,ZEMC=90°,DPo45Ḅ$DPA=PB,:,ZADP=ZBCP./CEM=ADEN,/DNE=/EMC=90=/DNB,PA=PB,:.ZBDP=ZADP,:.ZDEN=ZDBN,:.DE=DB,;.EN=BN,. .NoêḄ$D;(2)de4,OB,AB,AC,
123DABḄQᦪo90,.•.Z4OB=90°OA=OB=8,AB=8,ᵫ+14\ᳮ~AM=EM,EN=BN,AAEBḄ$é:.MN=-AB=4-f2.2ூDÄÅ⚪ὃÆÇᙊᕜ·ᳮØÙᳮῪj·Ḅᑨßឋj·Ḅᑁ·ßᳮ⚪Ḅᐵîᵨ᪀⌼Ὺc·j·⚪"#$ὃὃ⚪.1.+2020ïÎð.T21,8ᑖ467AABCOḄᑁej·44OḄcÃdäBE4,BCᑖ/ñ.+14tµZCAD=ZABCt+24AD=6,tC£ôḄ.ூὃDM5ᙊᕜ·ᳮwMN-.õḄöwMA-.j·ḄeᙊZ¸ூ⚪559ᙊḄᨵᐵᭆឋw67¢ᳮ¡ூᑖ᪆+14ᵫ·ᑖḄឋßᙊᕜ·ᳮ¦~NDBC=N4BC=NC4Qw
124+24ᵫᙊᕜ·ᳮ¦~CD=AC,ᵫõùú¦t.ூ§+14BC[ᑖZABD,:.ZDBC=ZABC,/CAD=NDBC,:.ZCAD=ZABC.+24ZCAD=ZABC,CD=AC9A£ôOḄcÃAD=6,i13CDḄ=—x—x;rx6=—ÿ.222ூ⚪ὃḄᙊᙊᕜᳮ ᮣ!"ᵨ$%ឋ'()*⚪+⚪Ḅᐵ-.4./2020ᓭ2,T24,8ᑖ79ᙠAABC>AC=BC,£A+X5DEOGH4ஹCஹD,JBCKE,HNDP//8C,JOF.RST/17VW+XYVWT/27AF=EF.ூὃKJ-. ῪḄᑨ\ឋ']U1-.XYVWḄᑨ\ឋ']M5Tᙊᕜᳮூ_⚪67Tbᳮcd]554T Ὺ\e]556Tfghi]559TᙊḄᨵᐵᭆmnឋ'ூᑖ᪆/17᪷q ῪḄឋ'rsABAC=ZB,᪷qXYuḄឋ'rsZADF=,Rsvwx=NCFD,᪷qXYuḄᑨrsBD//b,᪷qXYVWḄᑨrsᓽ};/27Rs=᪷qᙊᑁVWḄឋ'rsNECF+NE4P=180᪷qXYuḄឋ'rsNECF+NB=180°,Rs=P᪷q ῪḄᑨrsᓽ}.
125ூ(ST/1AC=BC,.•.ZBAC=ZB,DF!IBC.:.ZADF=ZB,ZBAC=NCFD,LZADF=NCFD,:.BD//CFfDF//BC,.• VWO3CF+XYVW;(2)AE,ZADF=ZB,ZADF=ZAEF, .ZAEF=ZB,VWAECb+ḄᑁVWZECF+ZEAF=]80°,BD//CF,.\ZECF+ZB=18O°,:.ZEAF=ZB,:.ZAEF=ZEAF,:.AE=EF.ூ⚪ὃXYuḄឋ'ᑨXYVWḄᑨᙊᑁVW ῪḄᑨ cᔠ"ᵨ Ybᳮ+(⚪Ḅᐵ-.1. 2020T24,10ᑖ79ᙠRtAABC>ZC=90°,ADXᑖN84CJBCKO4?DEGHAஹDḄOᑖJABஹACK£ஹF.
126(1)RST8c+Ḅᑗu;(2)qBE=8,sinB=—,RḄ;13(3)RSTAD2=ABAF.ூὃMRᙊḄᔠ⚪ூ_⚪55ET(enᐸᵨ]55DT9Ḅ]67Tbᳮcd]55AT\ᙊᨵᐵḄwᐵ]559TᙊḄᨵᐵᭆmnឋ'ூᑖ᪆(1)ᐜᑨs8//AC,rsNOD8=90°,ᓽ}rs¡¢](2)ᵫ┦¥ᦪ}rsin3=2=°=D,ᓽ}R(]BOBE+OD13(3)§HSAZMfisA/2}r©=©}r¡¢.ABADூ((T(1)98,EF,91ᑣ=ZODA=ZOAD,AZ)+N54cḄXᑖu,.-.ZOAD=ZCAD,:.^ODA=ZCAD,:.OD/1AC,:.ZODB=ZC=90°,
127ᙠOD.•.8C+OḄᑗu;(2)00=90OD5BOBE+OD□:.OD=5L.OḄ5](3)EF,AE+e/.ZAFE=90°=ZACB,.-.EF//BC, .ZAEF=ZB,¬ZAEF=ZADF,:.ZB=ZADF,¬Z.OAD=ACAD,M)AB^AFADL.AD_AFABAD'.AD2=ABAF.ூ⚪+ᙊḄᔠ⚪ὃᙊḄᨵᐵ ┦¥ᦪḄᑨឋ'¯°"ᵨ$%ឋ'Ybᳮ+⚪Ḅᐵ-.
