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HW-pg. 386-387 (16-26, 29-31)
6.1 to 6.3 Quiz FRIDAY 1-9-15
www.westex.org HS, Teacher Website
12-19-14
Warm up—Geometry CPA
Talk about plan for Ch.6
GOAL:
I will be able to:
1. classify polygons based on their sides and angles.
2. find and use the measures of interior and
exterior angles of polygons.
HW-pg. 386-387 (16-26, 29-31)
6.1 to 6.3 Quiz FRIDAY 1-9-15
www.westex.org
HS, Teacher Website
Name _________________________
Date ________
Geometry CPA
6.1 Properties & Attributes of Polygons
Today’s Goal
I will be able to:
1. classify polygons based on their sides and angles.
2. find and use the measures of interior and exterior angles of polygons.
Each segment that forms a polygon is a side of the polygon. The common endpoint of two
sides is a vertex of the polygon. A segment that connects any two nonconsecutive vertices is
a _______________.
Example 1: Identifying Polygons
Tell whether the figure is a polygon. If it is a polygon, name it by the number of sides.
a.
b.
c.
YOU TRY:
Tell whether the figure is a polygon. If it is a polygon, name it by the number of sides.
a.
b.
c.
All __________ are congruent in an equilateral polygon. All __________ are congruent in an
equiangular polygon. A _______________ polygon is one that is both equilateral and
equiangular. If a polygon is not regular, it is called irregular.
A polygon is __________ if it has one or more interior angles greater than 180°. If no
interior angles are greater than 180°, then the polygon is __________. A regular polygon is
always convex.
Example 2: Classifying Polygons
a.
b.
c.
YOU TRY:
a.
b.
How can we find the sum of the interior angle measures of a convex polygon?
In each convex polygon, the number of triangles formed is two less than the number of sides n.
Example 3: Finding Interior Angle Measures and Sums in Polygons
a. Find the sum of the interior angle measures of a convex heptagon.
b. Find the measure of each interior angle of a regular 16-gon.
c. Find the measure of each interior angle of pentagon ABCDE.
YOU TRY:
a. Find the sum of the interior angle measures of a convex 15-gon.
b. Find the measure of each interior angle of a regular decagon.
In the polygons below, an exterior angle has been measured at each vertex.
Example 4: Finding Exterior Angle Measures in Polygons
a. Find the measure of each exterior angle of a regular 20-gon.
b. Find the value of b in polygon FGHJKL.
YOU TRY:
a. Find the measure of each exterior angle of a regular dodecagon.
b. Find the value of r in polygon JKLM.
6.1 Practice
1. Name the polygon by the number of its sides. Then tell whether the polygon is regular or
irregular, concave or convex.
2. Find the sum of the interior angle measures of a convex 11-gon.
3. Find the measure of each interior angle of a regular 18-gon.
4. Find the measure of each exterior angle of a regular 15-gon.