yzj39102013-05-30TA获得超过4812个赞关注据题意先求得:△ABP≌△ADP.∠ABP=∠ADP.∴∠CDP=∠CBP.∵∠DEP=∠ACD(45°)+∠CPE.∠CBP=180°-∠BPC-∠BCP(45°),∵∠BPC=90°-∠CPE.∴∠CBP=180°-(90°-∠CPE)-45°=45°+∠CPE.∴∠DEP=∠CBP=∠CDP.∴PE=PD