Polygons

Lesson Plan - Get It!

Audio:

A polygon is a two-dimensional shape.

This means all polygons are flat shapes. Look at all the shapes below. Some of these shapes are polygons and some of them are not.

1. On a sheet of paper, make a T Chart (look at the picture below to see a T Chart).
2. On one side of the T Chart, draw the shapes that are polygons.
3. On the other side of the T Chart, draw all the shapes you think are not polygons.
4. When you are finished drawing the shapes into each category, write two sentences about why you sorted the shapes the way you did. Did you sort them based on how many lines they have? Did you sort them based on size?
5. Discuss your T Chart with a parent or teacher.
6. When you are finished writing about how you sorted your shapes, put your list to the side for later.

Let's learn how to identify polygons. So fa,r we know a polygon is a two-dimensional shape, just like all the shapes above; but, how can we tell what makes a shape a polygon? Look at the list below. This list will help you identify polygons.

Identifying Polygons

1. Polygons are two-dimensional shapes.
2. Polygons are only made up of straight lines.
3. Polygons are always closed shapes.

Now that you know how to identify polygons, take out your T Chart. Create another T Chart. See if you can correctly categorize each shape as being a polygon or not. When you are finished rewriting your list, check your answers below.

Polygons: Nonagon, Triangle, Rectangle, Square, Hexagon, Rhombus, Pentagon, Trapezoid, Decagon, and Octagon

Not a Polygon: Oval and Circle

Circles and ovals are not polygons because they have curved lines. Polygons only have straight lines.

Move on to the next section to get some more practice with polygons!