In these lessons, we will learn

- polygons,
- types of polygons
- simple or complex,
- convex or concave,
- equilateral,
- equiangular,
- regular or irregular

- names of polygons

**Related Pages**

Polygons

Angles Of Polygons

Quadrilaterals

Cyclic Quadrilaterals

More Geometry Lessons

A polygon is a closed shape that has three or more sides. Each side is a line segment. The line segments form the sides of the polygon.

The following are examples of polygons:

The following figures are **not** polygons:

The sides of a **simple polygon** do not intersect. In a simple polygon,
the line segments meet in pairs to form the vertices. Usually the word "simple" is omitted and the
word "polygon" is used to mean "simple polygon".

A **complex polygon** has intersecting sides.

A **convex polygon** has all angles less than 180°.

A **concave polygon** has at least one angle greater than 180°.
(**memory tool: concave has a "cave" in it**)

An **equilateral polygon** is a polygon which has all sides of the
same length. A rhombus is an example of an equilateral polygon.

An **equiangular polygon** is a polygon whose interior angles are equal.
A rectangle is an example of an equiangular polygon.

A **regular polygon** is a polygon with equal sides and equal angles
otherwise it is an **irregular polygon**. A regular polygon is
both equilateral and equiangular.

Some polygons have special names, depending on the number of sides they have.

The following table gives the names and properties of polygons with different number of sides. Scroll
down the page for more examples and solutions.

For polygons with more sides, it is easier and quite common to use a number to indicate the number of sides. For eg. 15-gon or 23-gon.

Practice the names of polygons with the following worksheets

Number of Sides In Polygons - Give the
number of sides.

Names of Polygons - Give the names of polygons.

**How to define a polygon?**

How to distinguish between concave and convex polygons?

How to name polygons?

**What is the difference between a regular and irregular polygons?**

The following video explains what are polygons, defines regular and irregular polygons and their features.

**Interior Angles in Convex Polygons**

The following video will show you the different types of polygons based on their sides and angles measures.

**Examples of classifying polygons**

Convex Hexagon, Concave Octagon, Convex Equilateral Nonagon.

Try the free Mathway calculator and
problem solver below to practice various math topics. Try the given examples, or type in your own
problem and check your answer with the step-by-step explanations.

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