Question

Find the missing side. Round to the nearest tenth.
A.7.4
B.4.4
C.6.4
D.5.4​

Answer 1

D. 5.4

Explanation:

Using trigonometric ratio

cos 39 = x/7

cross multiple

x = cos39(7)

x=5.4

Answer 2

option D

Explanation:

take 39 degree as reference angle

using cos rule

cos 39 = adjacent / hypotenuse

0.77 = x / 7

x = 7*0.77

x = 5.39

x = 5.4