Polygons Concept

What is a Polygon? Dr. Beth McCulloch Vinson Athens State University PT3 Grant Funding, Summer 2000

A polygon is… a many-sided figure a shape with three or more sides.

What do we need to know about polygons? ◆

How many sides does each polygon have?

◆

Do all polygons look the same?

◆

Can I know the name of a shape just by looking at it?

Triangle ◆

A triangle has three sides.

1

3

2

Square ◆

A square has four sides.

4 3

1

2

Pentagon ◆

A pentagon has five sides.

1

5

2

4 3

Hexagon and Heptagon A hexagon has six sides. (Hexagon and six both have an “x”.) ◆ A heptagon has seven sides. ◆

hexagon

heptagon

Octagon ◆

An octagon has eight sides. Count the sides. If this octagon was red and had the word “Stop” written on it, then you would know where we see a lot of octagons.

Let’s Review: The triangle is the smallest polygon. It only has three sides. ◆ A pentagon has five sides. ◆ A hexagon has six sides. ◆ A heptagon has seven sides. ◆ An octagon has eight sides. ◆

Match these. Triangle

eight sides

Heptagon

three sides

Octagon

seven sides

Match some more. Pentagon

four sides

Hexagon

five sides

Square

six sides

Key Question: A triangle is the smallest polygon because it has three sides. Can you have a twosided polygon? Why or why not? ◆

Two lines don’t close to make a shape. They make an angle.

1 2

The END A Project Developed for Preparing Tomorrow’s Teachers to Use Technology (PT3) By Dr. Beth McCulloch Vinson Athens State University, School of Education http://www.athens.edu/vinsobm