What is a polygon?
A simple closed curve made of three or more line-segments is called a polygon. A polygon has at least three line-segments.
The line-segments of a polygon are named by the sides in it. Poly means many and gon means sides. Thus a polygon has many sides.
The different polygons having definite number of sides are given names according to the number of sides.
(i) A polygon with three sides is called a triangle.
(ii) A polygon with four sides is called a quadrilateral.
(iii) A polygon with five sides is called a pentagon.
(iv) A polygon with six sides is called a hexagon.
Thus a polygon is given its name on the basis of the number of its sides.
Related Concepts on Geometry - Simple Shapes & Circle