Learn how to find equations of parallel lines, work out the gradient of perpendicular lines, and prove that given lines are parallel or perpendicular.

In math and statistics, you may occasionally need to calculate the slope of a line generated by coordinates in the (x,y) format. The slope is a value that indicates the rate at which the y value ...

Horizontal lines run left to right, parallel to the horizon, with slope 0 and equation y = k. Vertical lines run top to bottom, perpendicular to the horizon, with undefined slope and equation x = k.