Find the angle of elevation from horizontal distance and height above eye level.
The angle of elevation is the angle between the horizontal and the line of sight looking upward to an object. It is found using tan(θ) = opposite/adjacent = height/distance.
Angle of Elevation
θ = arctan(height / distance)
Whenever you look UP from horizontal — measuring building heights, incline of a ramp, spotting aircraft, etc.
Elevation looks up from horizontal; depression looks down from horizontal. They use the same formula but with height above or below eye level.