### Library Home CBSE - VII (Change Class)

Select subject
Congruence of Plane Figures

# Congruence of Plane Figures

If two objects are of exactly the same shape and size, they are said to be congruent.

Lesson Demo

If two objects are of exactly the same shape and size, they are said to be congruent. The relation between two congruent objects is called congruence.  The method of superposition examines the congruence of plane figures, line segments and angles.  Two plane figures are congruent if each, when superimposed on the other, covers it exactly.
Eg: Two plane figures, say,, are congruent if the trace copy of  fits exactly on that of .  We write

If two line segments have the same or equal length, they are congruent. Also, if two line segments are congruent, then they have the same length.
Eg: Two line segments, say, are congruent if they have equal lengths.  We write this
as

If two angles have the same measure, they are congruent. Also, if two angles are congruent, their measures are the same.
Eg: Two angles, say,  and , are congruent if their measures are equal.  We write this as  or as .  However, commonly, we write
.

A plane figure is any shape that can be drawn in two dimensions.