$解:PC=PD$
$過P作PM⊥OB,PN⊥OA$
$∴∠OMP=∠ONP=90°$
$∵OE平分∠AOB,∴∠MOP=∠NOP$
$在△OMP和△ONP中$
${{\begin{cases} {{∠OMP=∠ONP}} \\ {∠MOP=∠NOP} \\ {OP=OP} \end{cases}}}$
$∴△OMP≌△ONP(AAS)$
$∴PM=PN$
$∵∠PNO=∠AOB=∠OMP=90°$
$∴∠NPM=90°$
$∵∠CPD=90°$
$∴∠CPN+∠NPD=∠DPM+∠NPD=90°$
$∴∠CPN=∠DPM$
$在△DPM和△CPN中$
${{\begin{cases} {{∠DPM=∠CPN}} \\ {PM=PN} \\ {∠DMP=∠CNP} \end{cases}}}$
$∴△DPM≌△CPN(ASA)$
$∴PC=PD$