1 What is a polygon? a closed figure made by joining line segments Each line segment intersects exactly two others. line segments do not intersect *All.

1

What is a polygon?

a closed figure made by joining line segmentsEach line segment intersects exactly two others.line segments do not intersect

*All images are either original artwork or are used with permission from Microsoft Word and Microsoft Online Design Gallery.

2

Are these figures polygons?

yes

yes

no

no

3

What is a regular polygon?

A regular polygon is a polygon whose sides are all the same length and whose angles are all the same.

4

These are not examples of regular polygons.

The sides are not all the same length.

The angles are not all the same.

5

Let’s look at some different kinds of polygons.

triangle What is a three-sided polygon?

6

Polygons

parallelogram What is a four-sided figure whose opposite sides are parallel?

7

Polygons

rectangle What is a four-sided polygon whose sides and angles are all the same?

8

Polygons

square What is a parallelogram or rectangle with four equal sides and angles?

9

Polygons

rhombus What is a parallelogram whose sides are all the same length?

10

Polygons

trapezoid What is a four-sided polygon having exactly one pair of parallel lines?

11

Polygons

pentagon What is a five-sided polygon?

12

Polygons

hexagon What is a six-sided pentagon?

13

Polygons

heptagon What is a seven-sided pentagon?

14

Polygons

octagon What is an eight-sided pentagon?

15

Let’s review the polygons we‘ve learned about today.regular polygon

triangleparallelogramrectanglesquarerhombus

trapezoidpentagonhexagonheptagonoctagon

16

Can you identify these polygons?

Match these.

Triangle eight sides

Heptagon three sides

Octagon seven sides

Match some more. Pentagon four sides

Hexagon five sides

Square six sides

19

Using your geoboards or dot paper, replicate these polygons.