Polygon
Pronunciation: /ˈpɒl iˌgɒn/ Explain
A polygon is an nsided
closed
figure in a plane. Each of the sides of a polygon is a
straight
line segment. Since a polygon is closed,
each of the line segments is connected to another at both ends. Examples of
polygons are
triangles,
rectangles,
and pentagons.
An nsided polygon is called an ngon.
Parts of a polygon

Illustration 1: Parts of a polygon.


 Each of the line segments that define the polygon is called a
side or less commonly, an
edge.
 A point where two sides of the polygon meet is called a
vertex.
 Everything inside the polygon is called the
interior.
 Everything outside the polygon is called the
exterior.
 An
angle
at a vertex on the inside of the polygon is called an
interior angle.

Properties of polygons
 Straight
line segments  The edges of polygons are straight line segments. Each
line segment is connected to the other line segments at its endpoints.
 closed
 Polygons are closed figures. A pencil placed on one point on the edge
of the polygon and traced around the edge will return to the same point
without retracing.
 Connected
 Polygons are all in one piece.
 concave
or convex
 A polygon can be concave or convex. A polygon is convex if a line
segment drawn between any two points in the polygon remains within the polygon.
 Simple
or complex
 A polygon can be simple or complex. In a simple polygon, none of the edges cross.
Regular polygon
A regular polygon
is a polygon that is
simple,
convex
and
equilateral.
Some Types of polygons
Name  Sides  Illustration   Regular  
Central angle  Internal angle  Inradius/ apothem  Circumradius  Area 
ngon 
n 






triangle 
3 






quadrilateral 
4 






pentagon 
5 






hexagon 
6 






Table 2: Some Types of polygons 
More Information
 McAdams, David E.. Regular Polygon. allmathwords.org. Life is a Story Problem LLC. 3/12/2009. http://www.allmathwords.org/en/r/regularpolygon.html.
Cite this article as:
McAdams, David E. Polygon. 12/3/2018. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/p/polygon.html.
Image Credits
Revision History
12/1/2018: Removed broken links, updated license, implemented new markup. (
McAdams, David E.)
8/7/2018: Changed vocabulary links to WORDLINK format. (
McAdams, David E.)
12/31/2009: Added "References". (
McAdams, David E.)
9/3/2008: Expanded 'More Information'. (
McAdams, David E.)
7/12/2007: Initial version. (
McAdams, David E.)