# The Sum of the Interior Angles of a Pentagon

## Move around the points, but make sure the angles are still interior angles.

What is the sum of the interior angles?

Move around the points one more time and calculate the sum of the interior angles.

After calculating the sum, you should be able to notice that adding the interior angles of any triangle is always 180 degrees.

## Move around the points, but make sure the angles are still interior angles.

What is the sum of the interior angles?

Move around the points one more time and calculate the sum of the interior angles.

After calculating the sum of the interior angles of a quadrilateral (a polygon with four sides), you should be able to notice that sum is always 360 degrees.

## Notice how a square can be made up of two triangles. Since each triangles have a sum of 180 degrees for their interior angles, then the total sum for the quadrilateral is 360 degrees. ( 2 x 180 = 360 )

## A pentagon has five sides. Using the segment tool, create three triangles in the pentagon.

Since there are three triangles in the pentagon, assume the sum of interior angles of a pentagon.

Guess how many triangles can fit in a hexagon (a polygon with six sides).