Per cent grade and slope in degrees both indicate the amount that elevation changes over a certain distance, which determines how steep a hill or slope is. Per cent grade denotes the percentage of change in the elevation--for example, if a hill rises 20 feet over a 100-foot distance, it has a 20 per cent slope. The slope in degrees indicates the angle between the surface of a hill and level ground.

Divide the per cent grade by 100.

Take the arctangent of this number using a scientific calculator. Your calculator may have an "atan" button, or you may need to press the "2nd" or "inv" button, then the "tan" button.

Write "°" after the result to indicate degrees.