1. At the end of this chapter you will be able to: Define polygon
Chapter 17 Polygons
At the end of this chapter you will be able to:
Define polygon
Measure angles
Identify shapes such as quadrilaterals, rectangles, squares, parallelograms, and triangles
Find perimeter of various polygons
Find the area of various polygons
Find the square root of numbers
Words to Know
Plane Figure
A figure that has only length and width
Polygon
A plane figure with three or more sides
Angle
The space between two straight lines meeting at a point
Degree
The unit used to measure angles; the symbol for degree is
Quadrilateral
A plane figure with four sides
Rectangle
A plane figure with four sides and four ninety degree angles; the opposite sides of a rectangle are equal
Square
A plane figure with four equal sides and four ninety degree angles
Parallel lines
Lines that extend in the same direction at the same distance apart that never meet
Parallelogram
A plane figure with four sides; the opposite sides of a parallelogram are parallel
What is this a picture of??
______________________________

4. In this lesson, you will learn To identify figures as polygons
Types of Polygons
In this lesson, you will learn
To identify figures as polygons
To name polygons according to the number of sides
Words to Learn
Polygon: a closed ___________ formed by joining ____________ or more line segments at their endpoints
Non-consecutive vertices: any two vertices that are not next to _______ another
Diagonal: a line ____________ that joins two nonconsecutive vertices of a polygon
Soccer balls are covered with geometric figures called _____________. How many different kinds of figures can you find on the soccer ball?____________________

5. Number of Sides Common Name
Line segments form the sides of a polygon. Line segments have _________________.
Number of Sides
Common Name
Triangle
Octagon
Quadrilateral
Nonagon
Pentagon
Decagon
Hexagon
n-gon
Heptagon
Practice
Name the sides, the vertices, and the diagonals of each polygon. W N X V Y M O U Z L P T S
Sides:_____________________________ Sides:________________________________
Vertices:__________________________ Vertices:_____________________________
Diagonals:_________________________ Diagonals:____________________________

6. Sum of Interior Angles
Formula 1:
Sum of interior angles = (Number of sides – 2) x 180
= (5 – 2) x 180
= 3 x 180
= ____________
Practice
______- 2 x 180
______ x 180
_________________
______- 2 x 180
______ x 180
_________________
______- 2 x 180
______ x 180
_________________

7. 4 5 6 7 8 9 10 # of sides Sum of interior Angles
** Look through your notes from yesterday and the worksheet to fill in this chart. You will need it for todays activity.

8. Interior angle = sum of interior angle Number of sides
________________ 7 =
Practice
______________ 4 =
______________ 5 =
______________ =

9. Find the Missing Interior Angle
******Use the reference sheet we created for the sum of the interior angles. If you do not have it use the formula (# of sides – 2) x 180
Sum of the interior angles = x
720 = ____________ + x

10. __________ = _________+ _________ + ________ + _________ + X

14. Perimeter of Polygons
Perimeter- ___________ all sides
7 mm
How many sides does this shape have?________________________________

15. # of sides * measurement
12 cm