The grade (also called

**slope**, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal.Keeping this in view, how do you calculate the angle of a slope?

Convert the rise and run to the same units and then divide the rise by the run. Multiply this number by 100 and you have the percentage

**slope**. For instance, 3" rise divided by 36" run = .083 x 100 = an 8.3%**slope**.What is a 2% slope?

Surface Slope Conversions

Ratio | Percentage | Relative Measurement |
---|---|---|

1:48 | 2.0% | 1/4" per foot (actually 2.083%) |

1:20 | 5.0% | 19/32" per foot (actually 4.95%), or 5/8" per foot (actually 5.2083%) |

1:16 | 6.25% | 3/4” per foot |

1:12 | 8.33% | 1" per foot, or 6” of rise per 6' of run |

What is slope of line?

**Slope**is often denoted by the letter m; there is no clear answer to the question why the letter m is used for

**slope**, but it might be from the "m for multiple" in the equation of a straight

**line**"y = mx + b" or "y = mx + c". The direction of a

**line**is either increasing, decreasing, horizontal or vertical.