Here are a couple examples to show how these results can be used:

EXAMPLE 1:  :

What is the sum of the measures of the interior angles of the polygon on the right?

SOLUTION:    This is a pentagon (5 sides) and can therefore be filled with 3 triangles, so the sum of its interior angles is .

EXAMPLE 2:

What is the measure of each interior angle of a regular heptagon?

SOLUTION:       The exterior angles add to 360^o, and there are 7 of them.  Since it is a regular heptagon, the angles are all the same, so an exterior angle measures .  Therefore each interior angle measures  = .