Trigonometry
posted by AwesomeGuy .
Mountain Descent
A road sign at the top of a mountain indicates that for the next 4 miles the grade is 12%. Find the angle of the grade and the change in elevation for a car descending the mountain.

arctan .12 = 6.8°
the car ascends 12 ft for every 100 ft of horizontal travel, so it rises
.12 * 4 * 5280 = 2534 ft