Polygons

1
Polygons
Jessica Alfano EDUC 6584 Summer I
2
Do-Now

• Take out only your notebook and pencil
• On a clean sheet of paper answer the following to
  the best of your ability
• What is a polygon?
• Where in this classroom do you see examples of
  polygons?
• You have three minutes to complete this!!

3

• Where else in our environment do polygons exist?

4

• Lets look at a piece from our bathroom tile
• What shape is this?
• Square

5

• What is this?
• What shape is this?
• Octagon
• What do you do when you come to a stop sign?
• Stop!

6
Poly-gon

• From the Greek definitions
• poly means many
• gonia means angles
• Therefore, a poly-gon is a figure with many
  angles.
• Since, polygons have the same amount of angles as
  they do sides we call a polygon a many-sided
  figure.

7
Quadrilaterals

• A quadrilateral is any 4-sided polygon.

8
Some Polygons

• Triangle
• Rhombus
• Pentagon
• Hexagon

1
2
2
3
1
3
1
2
4
5
3
1
4
2
6
5
3
4
9
Polygons Cont'd
1
2
9
1
2
3
7
Heptagon
3
Nonagon
4
8
4
5
7
6
6
5
1
1
2
10
8
2
3
9
7
3
Octagon
Decagon
8
4
4
6
5
5
7
6
10
Lets Review
11
Some Definitions

• Regular PolygonA polygon whose side lengths are
  equal and angle measurements are equal.
• Irregular PolygonA polygon whose side lengths
  and/or angle measurements are not equal.

12
Lets Practice

• How many sides do these polygons have?
• So what polygon is this?
• Heptagon
• Which one is regular? Which one is
  irregular?

REGULAR
IRREGULAR
13
A Few More Definitions

• Parallel LinesLines in the same plane that do
  not intersect.

• PerpendicularLines in the same plane that
  intersect at a 90o angle.

ParallelogramA four-sided polygon whose sides
are parallel and equal in length. Important
Fact Both a rhombus and a square have four
equal sides, but a rhombus is a parallelogram.
14

• Which one of these quadrilaterals is a
  parallelogram?
• Why?

15
Any Questions?
16
Book Exercises

• Open up your books to page 200 and complete
  Exercises 1-10.

17
Fun Practice

• Go to http//www.mathgoodies.com/puzzles2004/puzzl
  es/ipolygon1.html
• Do the crossword puzzle for the remainder of
  class.