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JAMB Mathematics 1987 Question 41

Question 41

Trigonometry

A room is 12m long, 9m wide and 8cm high. Find the cosine of the angle which a diagonal of the room makes with the floor of the room.

  1. A.15/17
  2. B.8/17
  3. C.8/15
  4. D.12/17
Show the answer and explanation

Answer: A (15/17)

Explanation

The floor diagonal is √(144 + 81) = 15m and the room diagonal is √(225 + 64) = 17m. The cosine of the angle with the floor is 15/17.