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

A room is 12m long, 9m wide and 8m high. Find the cosine of the angle which a diagonal of the room makes with the floor of the room
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
  • A \(\frac{5}{17}\)
  • B \(\frac{8}{17}\)
  • C \(\frac{8}{15}\)
  • D \(\frac{12}{17}\)
Correct Answer: Option A
Explanation:
ABCD is the floor, by pythagoras
AC2 = 144 + 81 = \(\sqrt{225}\)
AC = 15cm
Height of room is 8m, diagonal of floor is 15m
∴ The cosine of the angle which a diagonal of the room makes with the floor is EC2 = 152
cosine = \(\frac{\text{adj}}{\text{hyp}}\) = \(\frac{15}{17}\)

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