Polygon:

A polygon is a plane figure bounded via more than four straight lines and containing more than four angles. If all the sides and angles of a polygon are equal then it is called a regular polygon, but if all the sides and angles are unequal, then it is called an irregular polygon. Polygons are named according to the number of their sides and angles.

(a) A pentagon is such which has five equal sides diagram (a).

(b) A hexagon is that that has six equal sides as in diagram (b).

(c) A heptagon is such which has seven equal sides diagram (c).

(d) An octagon is such which has eight equal sides in diagram (d).