PLEASE HELP!! DUE SOON :( #40

Types of polygon

Polygons can be regular or irregular. If the angles are all equal and all the sides are equal length it is a regular polygon.

Regular and irregular polygons

Interior angles of polygons

To find the sum of interior angles in a polygon divide the polygon into triangles.

Irregular pentagons

The sum of interior angles in a triangle is 180°. To find the sum of interior angles of a polygon, multiply the number of triangles in the polygon by 180°.

Example

Calculate the sum of interior angles in a pentagon.

A pentagon contains 3 triangles. The sum of the interior angles is:

180 * 3 = 540

The number of triangles in each polygon is two less than the number of sides.

The formula for calculating the sum of interior angles is:

(n - 2) * 180  (where n is the number of sides)