# Types of Polygon

Before we start learning about types of polygon, let us first learn the definition of a polygon. A polygon is a closed shape or figure that has a minimum of three sides. The term ‘poly’ means ‘many’ and ‘gon’ means ‘angle’. Thus, polygons have many angles.

## Definition of Polygon

In other words, a two-dimensional shape which is enclosed by a finite number of straight lines joining in the form of a closed-loop is called a polygon. The line segments which make the polygon are known as polygon’s sides or edges. Whereas the corner or the point where any two sides join is called vertex of the polygon.

## Classification of Polygons

Polygons are classified into various types based on the number of sides and measures of the angles. They are:

• Regular Polygons
• Irregular Polygons
• Concave Polygons
• Convex Polygons
• Pentagon Polygons

### Regular Polygon

In a regular polygon, all the sides of the polygon are equal and all the interior angles are the same.

Examples:

• A square having all its sides equal to 5cm and all the angles are at 90°.
• An equilateral triangle has all three sides equal to 10cm and angles measure to 60°. ### Irregular Polygon

A polygon that has an irregular shape, that means, the sides and angles of the polygon are not equal.

Example:

• A quadrilateral which has all its sides unequal.
• An isosceles triangle has only two of its sides equal and the third side has a different measurement. ### Convex Polygon

In a convex polygon, the measure of the interior angle is less than 180 degrees. It is exactly opposite to the concave polygon. The vertices of a convex polygon are always outwards.

Example: See the figure of an irregular hexagon, whose vertices are outwards. ### Concave Polygon

In a concave polygon, at least one angle measures more than 180 degrees. The vertices of a concave polygon are inwards as well as outwards. Quadrilateral polygon is also called a four-sided polygon or a quadrangle. The different types of the quadrilateral polygon are square, rectangle, rhombus and parallelogram. ### Pentagon Polygon

The five-sided polygon is called pentagon polygon. When all the five sides of the polygon are equal in length, then it is called regular pentagon otherwise irregular pentagon. ## Types of Polygon Chart

Now let us discuss, types of regular polygon according to the number of sides and measurement of angles.

 Name of the Polygons Sides Vertices Angle Triangle (also called Trigon) 3 3 60° Quadrilateral (also called Tetragon) 4 4 90° Pentagon 5 5 108° Hexagon 6 6 120° Heptagon 7 7 128.571° Octagon 8 8 135° Nonagon (also called Enneagon) 9 9 140° Decagon 10 10 144° n-gon n n (n-2)× 180° / n

All the shapes of the polygon from triangle to decagon are given here in the below figures, respectively. 