Rectilinear Figures Introduction

Rectilinear Figure

A plane figure bounded by straight lines is called a rectilinear figure.

Polygon

A closed rectilinear figure having three or more sides is called a polygon.

Types of polygon

Concave Polygon

If at least one angle of a polygon is greater than 180^o, then it is called a concave polygon.

Interior ÐDCB is greater than 180^o.

Convex Polygon

If every angle of a polygon is less than 180^o, then it is called a convex polygon.

Regular Polygon

It has all the angles and all the sides equal. In the figure, ÐA = ÐB = ÐC = ÐD = ÐE, and AB = BC = CD = DE = EA.

Name of Polygons with reference to the number of sides:

Triangles and quadrilaterals are also polygons with three sides and four sides respectively.

A diagonal of a polygon is a line joining any two non-adjacent vertices.