JAMB Mathematics 1989 Question 31

Question 31

Circle Theorems

MN is a tangent to the given circle at M, MR and MQ are two chords. If QM̂N is 60° and MN̂Q is 40°, find RM̂Q

Diagram for this question
  1. A.120°
  2. B.110°
  3. C.60°
  4. D.20°.
Show the answer and explanation

Answer: D (20°.)

Explanation

By the alternate segment theorem angle MRQ = angle QMN = 60°. In triangle MQN, angle MQN = 180° − 60° − 40° = 80°, so angle MQR = 100°. In triangle MRQ, angle RMQ = 180° − 60° − 100° = 20°.