Question

The given figure shows a circle with centre O such that chord RS is parallel to chord QT, angle PRT = 20° and angle POQ = 100°. Calculate:

(ii) angle QRP

Answer 1

Join PQ, RQ and ST.

Arc QP subtends `∠`QOPat the centre and `∠`QRP at the remaining part of the circle.
∴  `∠QRP = 1/2  ∠QOP`
⇒ `∠QRP = 1/2 xx 100° = 50°`