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JAMB Mathematics 1983 Question 7

Question 7

Trigonometry

In the above figure PQR = 60°, QPR = 90°, PRS = 90°, RPS = 45°, QR = 8cm. Determine PS.

Diagram for this question
  1. A.2√3cm
  2. B.4√6cm
  3. C.2√6cm
  4. D.8√6cm
  5. E.8cm.
Show the answer and explanation

Answer: B (4√6cm)

Explanation

In triangle PQR, PR = 8 sin 60° = 4√3cm. In triangle PRS, cos 45° = PR/PS, so PS = 4√3 × √2 = 4√6cm.