(a) In Fig. 1,AB is diameter of a circle centered at O.BC is tangent to the circle at B. If OP bisects the chord AD and ∠AOP=60∘, then find m∠C.(b) In Fig. 2, XAY is a tangent to the circle centered at O. If ∠ABO=40∘, then find m∠BAY and m∠AOB.