What is a Polygon?What is a Polygon?

Dr. Beth McCulloch Vinson

Athens State University

PT3 Grant Funding, Summer 2000

a many-sided figurea many-sided figure

a shape with three or a shape with three or more sides.more sides.

A polygon is…A polygon is…

What do we need to know What do we need to know about polygons?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?

TriangleTriangle A triangle has three sides.

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SquareSquare A square has four sides.

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PentagonPentagon A pentagon has five sides.

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Hexagon and HeptagonHexagon and Heptagon

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

A heptagon has seven sides.

hexagon heptagon

OctagonOctagon

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: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.Match these.

Triangle eight sides

Heptagon three sides

Octagon seven sides

Match some more.Match some more.

Pentagon four sides

Hexagon five sides

Square six sides

A triangle is the smallest polygon because it has three sides. Can you have a two-sided polygon? Why or why not?

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

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Key Question:Key Question:

The ENDThe 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