Answer:
Relative to x, the side of 16 is the hypotenuse, and the side of 9 is adjacent.
So we think, what trigonometric property relates hypotenuse and adjacent sides of a right triangle?
SOH CAH TOA
We can use the COSINE function to solve in this case, as we have both the ADJACENT SIDE (A) and the HYPOTENUSE (H).
Cosine = Adjacent/Hypotenuse
Cosine (x) = 9/16
Angle x = 55.8 degrees.
Let me know if this helps!