全国2018年中考数学真题分类汇?专题复习(?几何综合?答案不全) - 百度文库

ACE=MBE=30 ACM=ACE+ECM=75 AMAE=EM=MB MEB=EBM=30

1AME=2MEB=15

ߡCME=90

CMA=90-15=75=ACM AC=AM NΪCMе ANCM CMEM ANCM

2018𻪡ˮRtABCУACB=90㣬AC=12.DֱCBϣCA,CDΪACDE,ֱABֱCE,DEĽֱΪF,G.

1ͼD߶CBϣıACDE.

GΪDEе㣬FGij. DG=GFBCij.

2֪BC=9ǷڵD,ʹáDFGǵΣڣεڣ˵.

A F G E

C

D

24ͼ

B

2018𻪣ˮRtABCУACB=90㣬AC=12.DֱCBϣCA,CDΪACDE,ֱABֱCE,DEĽֱΪF,G.

1ͼD߶CBϣıACDE.

GΪDEе㣬FGij. DG=GFBCij.

2֪BC=9ǷڵD,ʹáDFGǵΣڣεڣ˵.

49 / 59

50 / 59

(2018üɽͼ٣ıABCDУACBDڵEAB=AC=BDMΪBCе㣬NΪ߶AMϵĵ㣬MB=MN.

1֤BNƽ֡ABE

2BD=1DNıDNBCΪƽıʱ߶BCij 3ͼڣFΪABе㣬FNFM֤MFNסBDC.

(2018̩)

51 / 59

2018ͼ٣ıBCDEУBC?CDDE?CDAB?AEֱΪC,DABC?ACM,N,FֱΪAB,AE,BEе㣬MN,MF,NF.

52 / 59

ϵͷ779662525#qq.com(#滻Ϊ@)