Polygon

Definition

A polygon is a closed geometric shape made of a finite number of straight line-segments joined end to end. In Greek, ‘poly’ means ‘many,’ and ‘gon’ means ‘angle’.

How many Sides does a Polygon Have

It should have a minimum of three sides but can have any maximum number of sides. A polygon is usually named based on the number of sides it contains. A polygon with n sides is called an n-gon.

Given below is the list of common polygons:

Types of Polygon with Their Properties

As shown in the above image, the most basic types of polygons found in everyday life are: 1) triangle, 2) quadrilateral, 3) pentagon, 4) hexagon, 5) heptagon, 6) octagon, 7) nonagon, and 8) decagon.

Given below is the list of the names of polygons with their basic properties:

Others Ways of Classifying Polygons

1) Based on Interior Angles

a) Convex Polygon

It is a polygon that has all its interior angles less than 180°. All the diagonals of a convex polygon lie inside the closed figure.

Triangles, all convex quadrilaterals, regular pentagon, and regular hexagon are common examples of a convex polygon.

b) Concave Polygon

Also known as a non-convex polygon, it is a polygon having at least one of its interior angles measuring more than 180°. Some diagonals of a concave polygon lie outside the closed figure.  

A dart or an arrowhead in quadrilaterals, some irregular pentagon and hexagon are common examples of the concave polygon.

2) Based on Side Lengths

a) Regular Polygon

It is a polygon having all sides of equal length and all interior angles of equal measure. A regular polygon is thus both equilateral and equiangular.

Triangle, quadrilateral, pentagon, and hexagon are common examples of the regular polygon.

b) Irregular Polygon

It is a polygon that has sides of unequal length and angles of unequal measure. Any polygon that is not regular is thus an irregular polygon.

Scalene triangle, quadrilaterals such as a rectangle, trapezoid or a kite, irregular pentagon, and hexagons are common examples of the irregular polygon.

Real Life Examples

• Pentagon, the large five-sided building that serves as the headquarters of the U.S. Department of Defense
• The Pyramids of Egypt with five sides
• The Bermuda Triangle
• The rectangle-shaped screen of our laptop, a television set, and mobile phones
• The tiles on which we walk in our homes and streets
• The wall of a building, the truss of a bridge

FAQs

• More Resources
  • Regular & Irregular Polygons
  • Convex & Concave Polygons
  • Area
  • Perimeter
  • Diagonals
  • Lines of Symmetry
  • Hierarchy
  • Similar Polygons
  • Inscribed & Circumscribed Polygons