Name: ____________________________
Polygons Class Work
Date:______ Period:_____
Ms. Anderle
Polygons: Class Work
A polygon is __________________ that has ______________________________.
A regular polygon is a polygon that is both ______________ and ________________.
Sum of the Interior Angles of a Polygon:
The formula for the sum of the interior angles of a polygon is:
180(n-2), where n represents the number of sides in the polygon.
If the problem asks you to find the measure of one angle of a regular polygon, use the
formula above and divide by the number of sides in the polygon.
*Remember* - This formula can only be used for regular polygons.
Formula:
180  n  2 
n
Examples:
1. Find the number of degrees in the sum of the interior angles of an octagon.
2. How many sides does a polygon have if the sum of the interior angles is 720˚?
3. How many degrees are there in the sum of the interior angles of a nine sided
polygon?
4. If the sum of the interior angles of a polygon equals 900˚, how many sides does
the polygon have?
5. What is the measure of the interior angle of a regular decagon?
6. What is the measure of the interior angle of a regular pentagon?
Exterior Angles of Polygons:
An exterior angle of a polygon is an angle that forms a ___________________ with one
of the angles of the polygon.
The sum of exterior angles of a polygon = _________. Therefore, to find the measure of
360
one exterior angle of a regular polygon is:
.
n
Examples:
1. Find the measure of each exterior angle of a hexagon.
2. The measure of each exterior angle of a regular polygon is 45˚. How many sides
does the polygon have?
3. How many degrees are there in the sum of the exterior angles of a dodecagon?
4. What is the measure of one exterior angle of a decagon?
5. What is the measure of one exterior angle on a stop sign?