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

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

What do we need to know about polygons? u How many sides does each polygon have? u Do all polygons look the same? u Can I know the name of a shape just by looking at it?

Triangle Triangle u A triangle has three sides

Square Square u A square has four sides

Pentagon Pentagon u A pentagon has five sides

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 Octagonseven sides

Match some more. Pentagon four sides Hexagonfive sides Squaresix sides

u 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. 2 1 Key Question:

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