Question 44
Circle TheoremsIn the diagram, PX is a tangent to the circle and RST is an equilateral triangle. Calculate ∠PTS.

- A.60°
- B.90°
- C.120°
- D.150°
Show the answer and explanation
Answer: C (120°)
Explanation
By the alternate segment theorem, ∠STX = ∠TRS = 60°. P, T, X lie on a straight line, so ∠PTS = 180° − 60° = 120°.