The slope of a straight line is equal to the slope's rise divided by its run. The rise and run can both be established by viewing the straight line on a graph. The rise over run equation can be used to solve for either the rise, if the run and slope are known, or for the slope if the rise and run are known. The slope will remain unchanged regardless of which points on the line are used to calculate it.
How to Calculate Slope
Choose two points on the line.
Count the number of units it will require to go from one point to another. The number of units left or right is the run. The number of units up or down is the rise. Movement left or down on the grid is a negative number. Movement right or up is a positive number. For example, if travel from point A to point B requires moving three units to the left, the line has a run of -3. If the same line requires moving three units up, the line has a rise of 3.
Divide the rise over the run. For example, if the rise is 3 and the run is -3, the result is -1. This result is the slope.
How to Calculate Rise
Express the equation slope is equal to rise divided by run.
Modify the equation to solve for rise instead of slope. To do this, multiply the slope by the run.
Solve the equation. For example, if the slope of the line is -1 and its run is -3, multiply -1 by -3. The result is the rise. In the example, the rise is equal to 3.