WAEC Mathematics 1993 Question 23

Question 23

Circle Theorems

Two chords PQ and RS of a circle when produced meet at K. If ∠KPS = 31° and ∠PKR = 42°, find ∠KQR

  1. A.11°
  2. B.73°
  3. C.107°
  4. D.138°
  5. E.149°
Show the answer and explanation

Answer: C (107°)

Explanation

In triangle KPS, ∠KSP = 180° − 31° − 42° = 107°. In cyclic quadrilateral PQRS, the exterior angle ∠KQR equals the interior opposite angle ∠PSR, so ∠KQR = 107°.