What is a Polygon Dr Beth Mc Culloch

What is a Polygon? Dr. Beth Mc. Culloch Vinson Athens State University PT 3 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? u How u Do many sides does each polygon have? all polygons look the same? u Can I know the name of a shape just by looking at it?

Triangle u A triangle has three sides. 1 3 2

Square u A square has four sides. 4 3 1 2

Pentagon u A pentagon has five sides. 1 5 2 4 3

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

Octagon u 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: u The triangle is the smallest polygon. It only has three sides. u A pentagon has five sides. u A hexagon has six sides. u A heptagon has seven sides. u 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? u 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 (PT 3) By Dr. Beth Mc. Culloch Vinson Athens State University, School of Education http: //www. athens. edu/vinsobm