In the diagram, PTS is a tangent to the circle TQR at T. Calculate <...

Explanation

RTS = RQT (angle between a tangent and a chord at the point of contact is equal to the angle in the alternate segment) But R = Q + T = 180

RQT = 180^o - (50 + 60)

= 180^o - 110^o

= 70^o

Since RQT = RTS = 70^o