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WAEC Mathematics 2022 Question 30

Question 30

Circle Theorems

In the diagram, MNR is a tangent to the circle centre O at N and ∠NOS = 108°. Find ∠OSN.

Diagram for this question
  1. A.72°
  2. B.42°
  3. C.36°
  4. D.18°
Show the answer and explanation

Answer: C (36°)

Explanation

OS = ON (radii), so triangle ONS is isosceles: ∠OSN = (180° − 108°)/2 = 36°.