Calculate angle, hor, vert, incline distances:

Angle / distance calculation using 2 out of 4 inputs variables.
vertical distance : 1 1 1 1 1 1 1 1
incline distance : 14 10 7 6 5 4 3 2
angle approx ~ : 4 6 8 10 12 15 20 30

Formula with <5% accuracy for angles <30 degrees, so ratio >2:

angle = 60 * vertical distance / incline distance

or in other words:

angle = 60 / ratio(incline : vertical)