Answer:
x = (9√2)/2
Explanation:
Reference angle = 45°
Hypotenuse length = 9
Adjacent length = x
Apply the trigonometric ratio CAH:
Cos 45° = Adj/Hyp
Cos 45° = x/9
Multiply both sides by 9
9*Cos 45 = x
9*1/√2 = x (cos 45 = 1/√2)
9/√2 = x
Rationalize
(9*√2)/2 = x
x = (9√2)/2