passwella.
Menu

JAMB Mathematics 1979 Question 14

Question 14

Circle Theorems

In the figure below PQ and QR are chords of the circle PQR. QRS is a straight line and PR equals to RS. <PSR is 20°. What is the size of <POQ?

Diagram for this question
  1. A.70°
  2. B.90°
  3. C.80°
  4. D.40°
  5. E.60°
Show the answer and explanation

Answer: C (80°)

Explanation

PR = RS, so <RPS = <RSP = 20° and the exterior angle <PRQ = 40°. The angle at the centre is twice this: <POQ = 80°.