3.8 SUMMARY

1. Polygon –   Polygon is a combination of two Greek words Polus   +   Gonia, in which Polus means many and Gonia means Corner or angle.
2. Classification of Polygons

Polygons are classified as per their sides or vertices they have.

( a )    Triangle   –  A triangle has three sides and three vertices.

A triangle is of three types Equilateral, Isosceles and Scalene.

( b )    Quadrilateral   –   A quadrilateral has four sides and consecutively four  vertices.

( c )    Pentagon    –    ( Penta stands for five ) A pentagon has five sides and five vertices.

( d )    Hexagon    –    ( Hexa stands for six ) A hexagon has six sides and six vertices.

( e )    Heptagon   –    ( Hepta stands for seven ) A heptagon has seven sides and seven vertices.

( f )     Octagon     –    ( Octa stands for eight ) an octagon has eight sides and eight vertices.

( g )    Nonagon    –    ( Nona stands for nine ) A nonagon has nine sides and nine vertices.

( h )    Decagon     –    ( Deca stands for ten ) A decagon has ten sides and ten vertices.

1. Diagonals: A line segments which connects two non  –  consecutive vertices of a polygon is called diagonal.

The diagonals of a rectangle are always equal.

1. Quadrilaterals are one type of polygon which has four sides and four vertices and four angles along with 2 diagonals. There are various types of quadrilaterals.