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: 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})