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JAMB Mathematics 1988 Question 40

Question 40

Bearings

Alero starts a 3km walk from P on a bearing 023°. She then walks 4km on a bearing 113° to Q. What is the bearing of Q from P?

  1. A.26°52'
  2. B.53°8'
  3. C.76°8'
  4. D.90°
Show the answer and explanation

Answer: C (76°8')

Explanation

The two legs are at right angles (113° − 23° = 90°). At P the angle between the first leg and PQ is tan⁻¹(4/3) = 53°8'. The bearing of Q is 23° + 53°8' = 76°8'.