Download L2 - Exterior Angles of Polygons

Chapter 8, Lesson 2
Date:
Objective: Learn to find the sum of the exterior angles of a polygon and the measure of one exterior angle
of a regular polygon.
A. Wups
Solve for x.
1.
2.
B. Exterior Angles of Polygons
Exterior Angle
An angle that forms a linear pair with an internal
angle of a polygon.
Key Point
The measure of an interior angle plus the measure
of an exterior angle always equals: ________
Formula
Sum of the Exterior Angles
of a Polygon
360˚
ONE Exterior Angle of a
Regular Polygon
360
n
1
C. Examples
1. Find the sum of the measures of the exterior angles of each polygon?
a. Triangle
b. 16-gon
2. Find the measure of an exterior angle for each regular polygon?
a. Triangle
b. Quadrilateral
c. 15-gon
d. 36-gon
3. Find the measure of an exterior angle given the number of sides of a regular polygon.
a. 40
b. 18
c. 12
d. 24
4. Find the measures of an interior angle and an exterior angle given the number of sides of each regular
polygon. Round to the nearest tenth, if necessary.
a. Quadrilateral
2
b. Dodecagon
5. Find the missing angles.
a.
b.
6. Solve for x for the following regular polygon.
a.
3
b.
D. Summary
Complete the following table.
Regular Polygon
Measure of an
Interior Angle
Measure of an
Exterior Angle
Triangle
Square
Hexagon
Nonagon
4