4角平分线角平分线专题训练(四)角平分线解:BE平分BAC,C90,EDAB,DEEC,DE垂直平分AB,AEBE,ACAECE,ACBEDE解:O是A,B的平分线交点,且OP BC,OQAC,ORAB,BRBP,PCQC,AQAR,设BPx,则PC8x,QC8x,AQ1x,AR1x,BRBPx,ARBR7,1xx7,解得x3,即BP3,CQ5,AR4解:在BED和CFD中,BEDCFD90,EDBFDC,BDCD,BEDCFD(AAS),DEDF,又DEAB,DFAC,点D在BAC的平分线上解:过M作MN AD,DM平分ADC,MNAD,C90,MNMC,在RtDNM和RtDCM中,NMCM,DMDM,DNMDCM(HL),CDDN,同理,ANAB,ADANDN,ADCDAB