# Find the angle between two chords passing through points where lines are tangent to the circle

In the given figure, PQ and PR are tangents to the circle with centre $O$ and $S$ is a point on the circle such that $\angle{SQL}={50}^{\circ}$ and $\angle{SRM}={60}^{\circ}$. Find $\angle{QSR}.$

What I've tried,

Join $OQ$ and $OR$. Since the line joining the point of contact of the tangent to the centre of the circle is equal to $90^{\circ}$.