A polygon consists of three or more line segments, called sides, whose endpoints connect end-to-end to enclose an area. Some examples of polygons include triangles, squares, and rectangles. Polygons are denoted algebraically by writing the names of their vertices in consecutive order, either clockwise or counterclockwise. Polygons come in different shapes and sizes, and there is no maximum limit to the number of line segments used to form a polygon. Polygons with more than four sides are commonly named using the Greek prefix for the number of sides, followed by -gon. Think about the name in the applet before pressing ⬆️ and ⬇️ to increase or decrease the number of sides. Polygons can be classified according to their side lengths. Whenever all sides of a polygon are the same length, it is said to be a regular polygon. Otherwise, a polygon is considered to be irregular.

Additionally, depending on the shape, a polygon can be convex or concave. This last classification is based on the measure of the interior angles of the polygon.