Year 7 Interactive Maths - Second Edition

## Polygons

A polygon is a closed plane figure with three or more sides that are all straight.

Some examples of polygons are shown below.

The following figure is not a polygon as it is not a closed figure.

A circle is not a polygon as it does not have straight sides.

Polygons are named according to the number of sides.  The names of the most common polygons are given below:

### Concave Polygon

If a polygon has a reflex angle, then it is said to be a concave polygon.

An example of concave polygon is shown below.

### Convex Polygon

If a polygon has no reflex angle, then it is said to be a convex polygon.

Examples of the convex polygons are shown below.

### Regular Polygon

A regular polygon's sides are all of the same length and its angles are the same size.

For example, a square is a regular polygon.

Examples of regular polygons are shown below.

### Irregular Polygon

If a polygon is not a regular polygon, then it is said to be an irregular polygon.

For example, the quadrilateral shown below is an irregular polygon.

###### Key Terms

Copyright © 2000-2017 mathsteacher.com Pty Ltd.  All rights reserved.
Australian Business Number 53 056 217 611

Copyright instructions for educational institutions

Please read the Terms and Conditions of Use of this Website and our Privacy and Other Policies.
If you experience difficulties when using this Website, tell us through the feedback form or by phoning the contact telephone number.