6-1 Properties and of Polygons
DoAttributes
Now
In the polygon below, find the sum of the measures of the set of exterior angles.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons

Objectives
Find and use the measures of exterior angles of polygons.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons

Remember!

An exterior angle is formed by one side of a polygon and the extension of a consecutive side.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
• The sum of the measures of the exterior angles of a convex polygon is 360o.
– As if you were traveling in a circle!
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Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
Example :
Find the measure of each exterior angle of a regular 20-gon.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
Your Turn
Find the measure of each exterior angle of a regular dodecagon.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
Example:
Find the value of b in polygon
FGHJKL.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
Your Turn
Find the value of r in polygon JKLM.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
Your Turn
External Angles of Polygons

Find the measure of exterior angle a.

Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
Your Turn

Ex. 3: Finding the Measure of an Exterior
Angle

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Holt McDougal Geometry

6-1 Properties and Attributes of Polygons
Art Application
Ann is making paper stars