The slope is equivalent to the rise over run. Since the slope of the bike ramp is ¼, the rise is equivalent to 1 and the run is equivalent to 4. To get the angle of the bike ramp make with the ground, let us use the equation tanθ= rise/run.
Therefore, tanθ= ¼.
Θ=tan-1 (1/4)
So the angle of the bike ramp is Θ= 14degrees