Answer:
38.7°
Step-by-step explanation:
You are basically looking at a triangle with a 90° angle (check picture).
Since we are looking for the ramp's angle and are given the length of the opposite and the hypothenuse, we have to solve the following equation:
[tex]sin (\alpha) = opposite / hypothenuse= 5 ft/8ft[/tex]
which is equivalent to
[tex]\alpha = sin^{-1}(5/8)\approx 38.7\deg[/tex]