The angle that the ramp makes with the ground is 11.54°
Step-by-step explanation:
From the image attached, we can see that the length of 17 1/2 ft corresponds to the hypotenuse in a right triangle, the length of 3 1/2 ft corresponds to the opposite side.
We can use the fact that the sin(θ) = to find the angle that the ramp makes with the ground.