passwella.
Menu

WAEC Mathematics 2015 Question 20

Question 20

Circle Theorems

In the diagram, O is the centre of the circle, RT is a diameter, ∠PQT = 33° and ∠TOS = 76°. Find the size of angle PRS.

Diagram for this question
  1. A.76°
  2. B.71°
  3. C.38°
  4. D.33°
Show the answer and explanation

Answer: B (71°)

Explanation

∠PRT = ∠PQT = 33° (same segment) and ∠TRS = ½ × ∠TOS = 38° (angle at centre is twice angle at circumference), so ∠PRS = 33° + 38° = 71°.