In the figure, T is the centre of the circle, QT is parallel to RS and ∠RTS = 112°. Find the values of
- ∠r
- ∠s
- ∠t
(a)
∠r
= (180° - 112°) ÷ 2
= 34° (Angle properties within a circle)
(b)
∠QTR = ∠r = 34° (Alternate angles)
∠s
= (180° - 34°) ÷ 2
= 73° (Angle properties within a circle)
(c)
∠t
= 360° - 112° - 34°
= 214° (Angles at a point)
Answer(s): (a) 34°; (b) 73°; (c) 214°