$PQ$ is a tangent to the circle at a point $Q$. $O$ is the centre of the circle and $QR$ is a diameter. If $\angle POR =120^{\circ}$ then $\angle OPQ =$.........
If tangents $PA$ and $PB$ from a point $P$ to a circle with centre $O$ are inclined to each other at angle $80^{\circ}$. Then $\angle POA =$...........