# Sum of the Interior Angles of a Pentagon

- Author:
- Leslie Pedroza

The interior angles of a shape are found at each vertex on the inside of the shape. Observe the triangle below and its' interior angles.

What is the sum of the interior angles of the triangle?

Move around one of the points of the triangle.

After you have moved one of the points of the triangles, what is the sum of the interior angles now?

Below is a pentagon. Within the pentagon, three triangles are drawn within from one point to another.

From the previous information about triangles, what is the sum of the interior angles of the pentagon?

Now use the equation for the sum of interior angles: (n-2) × 180°, n is the total number of sides of a pentagon Calculate the sum of interior angles for a pentagon. Did you get the same answer as the question before?

The polygon below is also a pentagon, but it is a regular. A polygon is defined to be regular when both angles and sides are equal.

What is the angle measurement for each interior angle of the regular pentagon?