PQL and PRM are tangents to the circle with centre o at the points Q and R ,respectively and S is a point on the circle such that angle SQL=50 and angle SRM=60. Find angle QSR.
Here ∠OSQ = ∠OQS = 90°–50° = 40° and ∠RSO = ∠SRO =
90° – 60° = 30°. Therefore, ∠QSR = 40° + 30° = 70°.