For the inner circle, BC is a chord and OP ⊥ BC .
We know that the perpendicular to a chord, from the centre of a circle, bisects the chord.
∴ BP = PC
By Pythagoras theorem,
For the outer circle, AD is the chord and OP ⊥ AD .
We know that the perpendicular to a chord, from the centre of a circle, bisects the chord.
∴ AP = PD
By Pythagoras Theorem,