Askateboard ramp had a slope of 2/5. which is the closest to the angle the ramp make with the ground?

Note that tan(x) = sin(x)/cos(x) is related to m = rise/run = Δy/Δx. If Δy = 2 and Δx = 5, then sin(x) = 2 and cos(x) = 5.

Therefore

tan(x) = 2/5

x = arctan(2/5)

x ≈ 21.8°

Hope this helps!