In the given fig, PQ is tangent at a point R of the circle with centre O. If ∠TRQ=30∘, find ∠PRS.
In Fig. 8.66, tangents PQ and PR are drawn from an external point P to a circle with centre O, such that ∠RPQ=30∘. A chord RS is drawn parallel to the tangent PQ. Find ∠RQS.