We will be using the cosine function to figure this out.
The ramp, ground, and platform form a right triangle.
The hypotenuse is 29, and the side adjacent to ∠x is 20.
SO:
Cos ∠x = 20/29
Cos ∠x = 0.68965517241379
Use the function on your calculator to find what angle has a Cos of 0.6896551
Cos 0.6896551 = 46.397°
ANSWER: the angle of elevation is 46.4°
Hope this helps! God bless. :)