初中基本图形及基本结论归纳

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1、序号基本图形基本结论AD=BCAC=BDcZAOC二ZBODw2ZAOD=ZBOCOD丄OE3ZCAD=ZB4ZP=ZA+ZB+ZC5ZA+ZB=ZC+ZD6ZB二ZD78ZP=ZA/29ZP=90°-ZA/2ZBAD=ZCAD2=BD・CDAB2=BD・BCAC2=CD•BC子母型①②③④ZP=90°+ZA/21213141516171819CD为小线ABDCbcADA型假A型假子母型DxE、F、G.H为中点DE〃BC=>«=>①AC平分ZBAD②AB=CB③BC〃AD“二推一”AD二BD二AC二DCA

2、C:BC:AB=1:V3:2AP平分ZBACAB=ACBD=CD③AD丄BC:④Z1=Z2PB=PCa—-fcfi：—”一推一㊉㊉f㊉㊉DE=BC/2DE//BCEF=(AD+BC)/2EF〃BC〃AD四边形EFGH为平行四边形ADAEADAEDEBD~CDAB~~AC~~BCADAEADAEDEBD~CDAB'~AC~~BCADAEDEAB'~AC~~BCAC2=AD•AB2324蝶型25规型26272829BC:AC:AB=1:1:V2BPPBIt①②;③i④｝⑤过圆心垂直于弦平分弦平分弦所对的优弧平

3、分弦所对的劣弧二推三㊉㊉-►㊉㊉㊉R2=d2+(a/2)2d+h=RAB为直径ZC=90°ADPAPDBC~'PC~~PBPAPDADPC~~PB~~BCPBPDBDPCPAACPB•PA=PD•PCABBCACBD~~AB~~ADAB2=BD•BCZA=ZDCEZA+ZDCB=180°①②③过圆心过切点垂直于切线“二推一”31A厂二—BPA=PBZAPO=ZBPO32ABZ1=ZPZ2=ZC33A=>Ch、02>A三点共线3401丄02AC=BC