Calculating the slope of a line on a graph is a fundamental skill in algebra, geometry, and calculus. The slope indicates the steepness of the line and can also show the relationship between two ...

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.

Whether you are sketching graphs in mathematics, understanding directions in geography, or reading blueprints in design class, horizontal and vertical lines are concepts you cannot avoid. They form ...