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
A. \(\frac{5}{17}\) B. \(\frac{8}{17}\) C. \(\frac{8}{15}\) D. \(\frac{12}{17}\)
Correct Answer: 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 = \(\frac{\text{adj}}{\text{hyp}}\) = \(\frac{15}{17}\)
