# L6.1 Polygon Interior Angle Sum

- Author:
- Karen Rowe, jmamer, Marie Mueller

## Explore Convex Polygon Angles' Measure Sum

Use this applet to study patterns with interior angle sums of polygons.

## Explore Concave Polygon Angles' Measure Sum

Since one of the angles forces the polygon to be CONCAVE, does it affect the polygon angle sum?

## Draw in the auxiliary segments: diagonals.

## Draw in the auxiliary segments: diagonals.

How many diagonals are there from the vertex E in the quadrilateral? How many diagonals are there from the vertex D in the quadrilateral? Did the amount change? How many triangles are formed by the diagonals?

How many diagonals are there from the vertex H the pentagon? How many diagonals are there from the vertex L the pentagon? Did the amount change? How many triangles are formed by the diagonals?