passwella.
Menu

WAEC Mathematics 2020 Question 43

Question 43

Circle Theorems

In the diagram, O is the centre of the circle, PQ and RS are tangents to the circle. Find the value of (m + n).

Diagram for this question
  1. A.120°
  2. B.90°
  3. C.75°
  4. D.60°
Show the answer and explanation

Answer: B (90°)

Explanation

The tangents touch at the ends of a diameter, and the angle at the third point is 90° (angle in a semicircle). Each of m and n is 90° minus the triangle's angle beside it, so m + n = 180° − 90° = 90°.