# Slopes, Grades and Angles

# Arctan Function using Rise & Run

The arctan function is used to obtain an angle from the tangent trigonometric ratio, which is the ratio between the side opposite to the angle, the rise, and the adjacent side, the run, of a right angled triangle.

Or in a simpler form, the arctan function can be used to calculate the angle of a slope by dividing the rise by the run measurement.

From the image above:

Atan ( rise ÷ run)
the rise = 11 feet
the run = 25 feet
11 ÷ 25 = 0.44
Atan ( 0.44 ) = 23.74949449°

### Rise and Run/Arctan Function

#### Calculation

- the rise in feet and inches
- the run in feet and inches

#### Results

- angle in radians
- angle in degrees

### Slopes, Grades and Angles