Originally Posted by
Road Fan
Ok, wikipedia says it's the percent rise divided by run. If the base of a right triangle is horizontal then it is the run. The rise is the vertical leg of the right triangle. Divide rise by run and multiply by 100. The hypotenuse does not enter into the calculation.
I could easily be getting in over my head here
, but the reason I used the hypotenuse was to take known values (the distance traveled and the elevation gain) to solve the unknown value (the run).