## Polygons

### Polygon

A **polygon** is a closed figure that is the union of line segments in a plane. A polygon has three or more sides.

A polygon has the same number of angles as sides.

Polygons can be classified as either **convex** or **concave**.

A polygon is **convex** if no line that contains a side of the polygon contains a point in the interior of the polygon. In a** convex** polygon, each interior angle measures less than 180 degrees.

**Concave** polygons “cave-in” to their interiors, creating at least one interior angle greater than 180 degrees (a reflex angle).

**Read also:**

- Different Types of Polygons
- Perimeter of a Polygon
- Area of Polygons and Circles
- Interior Angles of Regular Polygons
- Sum of Interior Angles of a Polygon

### Types of Polygons

Listed below are some of the more commonly used polygons.

Do not assume that the diagrams under the “Graphic” column are “regular” polygons. Do not assume any specific details about the diagrams such as the length of the sides or measures of the angles.

A polygon is **equilateral** if all of its sides are of the same length.

A polygon is** equiangular** if all of its angles are of equal measure.

A **regular polygon** is a polygon that is both equilateral and equiangular.