Pls sir I have problem ????????

Dear student,
Answer :

By given information ,we draw our figure ,As  :

Now 

In $∆$ APO  and $∆$ BPO

OA    =   OB                                 ( As these are the radius of the circle )

$\angle$  APO  =  $\angle$ BPO                      ( As we draw to perpendiculars on side AB from centre O to P )

OP    =   OP                                 ( Common side )

So,

 $∆$ APO $\cong$ $∆$ BPO                      (  By  SAS rule  )

Hence 

AP    =    BP                                ( by  CPCT )                       ( Hence proved )
Regards