Answer:
x ≈ 57.8°
Step-by-step explanation:
The relevant trig relation is the one that relates the side adjacent to the angle to the hypotenuse and the angle:
Cos = Adjacent/Hypotenuse
cos(x) = 8/15
The value of x is found using the inverse cosine function:
x = arccos(8/15)
x ≈ 57.8°
