The steepness of any incline can be measured as the ratio of the vertical change to the horizontal change. For example, a 5% incline can be written as
5\100
, which means that for every 100 feet forward, the height increases 5 feet.
In mathematics, we call the incline of a line the slope and use the letter m to denote it. The vertical change is called the rise and the horizontal change is called the run.
Slope
m = vertical change by horizontal
change = t by t
The rise and the run can be positive or negative. A positive rise corresponds to a vertical change up and a negative rise corresponds to a vertical change down. A positive run denotes a horizontal change to the right and a negative run corresponds to a horizontal change to the left. Given the graph, we can calculate the slope by determining the vertical and horizontal changes between any two points.