Two triangles are said to be congruent if all three corresponding sides
are equal and all the three corresponding angles are equal in measure.
These triangles can be slides, rotated, flipped and turned to be looked
identical. If repositioned, they coincide with each other. The symbol of
congruence is’ ≅’.
Types of congruency
SAS
If two sides and the included angle of one triangle are equal to the corresponding two sides and the
included angle of the other triangle, then the two triangles are congruent by SAS [Side Angle Side]
congruency.
ASA
If two angles and the included side of one triangle are equal to the corresponding two angles and the
included side of the other triangle, then the two triangles are congruent by ASA [Angle Side Angle]
congruency.
AAS
If two angles and one side of one triangle are equal to the corresponding two angles and one side of
the other triangle, then the two triangles are congruent by AAS [Angle Angle Side] congruency.
SSS
If three sides of one triangle are equal to the three sides of the
other triangle, then the two triangles are congruent by SSS [Side
Side Side] congruency
RHS
If the hypotenuse and one side of a right angled triangle is equal to the
hypotenuse and corresponding side of another right angled triangle, then the
two triangles are congruent by RHS [Right Angle Hypotenuse Side] congruency