1. Lesson 8.2 (Part 2) Exterior Angles in Polygons
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2. What is the sum of the measures of the exterior angles of a polygon?
Draw a convex polygon with 3, 4, 5, etc sides (regular polygons work best for this example).
Draw an exterior angle from each vertex.
Given the interior angle measure, calculate the exterior angle measures and add them together. Look for a pattern.
Polygon
# of degrees in 1 interior angle
# of degrees in 1 exterior angle
Sum of exterior angles
Triangle
Quadrilateral
Pentagon
Hexagon

3. Polygon Exterior Angles Theorem
The sum of the measures of the exterior angles of a convex polygon is 360⁰.
Example 1: Find the sum of the exterior angles of a convex heptagon.
Example 2: Find the sum of the exterior angles of a convex 12-gon.

4. Find the value of x.
89⁰ 3x
60⁰
73⁰
116⁰ x
92⁰
46⁰

5. Find the value of x. 3x
70⁰ x x 2x
75⁰
110⁰
65⁰

6. Assignment:
8.2 B Worksheet