Chapter 3B day2 Notes
October 28, 2013
Chapter 3B Day 2
Polygon Angle-Sum Theorem
The sum of the interior angles of a convex polygon is:
(n-2)180, where "n" is the number of sides of the polygon.
NEW INFO!!
The sum of the exterior angles of a convex polygon is
ALWAYS, ALWAYS, ALWAYS 360o
Today we are going to look at Regular Polygons
What is a regular regular polygon?
A polygon with congruent sides and congruent angles.
3b-2
Chapter 3B day2 Notes
October 28, 2013
Let's look at regular polygons and their exterior angles.
What is the sum of the
exterior angles?
What is the measure of
each exterior angle?
What is the measure of
each interior angle?
How did you find it?
3b-2
What is the sum of the
exterior angles?
What is the measure of
each exterior angle?
What is the measure of
each interior angle?
Chapter 3B day2 Notes
What is the sum of the
exterior angles?
What is the measure of
each exterior angle?
What is the measure of
each interior angle?
3b-2
October 28, 2013
What is the sum of the
exterior angles?
What is the measure of
each exterior angle?
What is the measure of
each interior angle?
Chapter 3B day2 Notes
What is the sum of the
exterior angles?
What is the measure of
each exterior angle?
What is the measure of
each interior angle?
3b-2
October 28, 2013
What is the sum of the
exterior angles?
What is the measure of
each exterior angle?
What is the measure of
each interior angle?
Chapter 3B day2 Notes
October 28, 2013
Suppose I know the sum of the interior angles of a polygon,
can I find the number of sides?
The sum of the interior angles of a polygon is 1080; how
many sides does it have?
The sum of the interior angles of a polygon is 2880; how
many sides does it have?
3b-2
Chapter 3B day2 Notes
October 28, 2013
Suppose I know the measure of an interior angle of a regular
polygon, can I find the number of sides?
m of an interior angle of a reg is:108o
How many sides does it have?
m of an interior angle of a reg is:120o
How many sides does it have?
3b-2
Chapter 3B day2 Notes
October 28, 2013
Suppose I know the measure of an exterior angle of a regular
polygon, can I find the number of sides?
m of an exterior angle of a reg is:120o
How many sides does it have?
m of an exterior angle of a reg is:40o
How many sides does it have?
3b-2
Chapter 3B day2 Notes
October 28, 2013
Complete the table for regular polygons.
Number of sides
3
4
5
6
8
9
10
Measure of each int <
150
Measure of each ext <
Number of sides
24
20
Measure of each int <
Measure of each ext <
165
12
10
172
9
175
6
Assignment: pp 147-150 (22, 24, 32, 34, 38, 40-44even, 64-70 even)
3b-2