The term graph has several different meanings in mathematics. It can mean the interpretations of numbers, including bar graphs, pie charts, and line graphs. For example, a pie chart (graph) is often used to represent percents, such as a breakdown of where a taxpayer’s money is spent in the various government agencies for a certain year.

In analytic geometry, a graph is simply a way of plotting—thus, visually representing—points, lines, curves, and solids in order to understand and interpret certain geometric figures and to solve equations. For example, solving an equation with one to two variables (usually written as x and y, or two dimensions) results in a curve on a graph (note: a line is considered a curve in geometry). Equations that contain three variables (usually as x, y, and z, or three dimensions) result in a surface.