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can you explain me about congruence of triangles

In geometry, two figures or objects are congruent if they have the same shape and size, or if one has the same shape and size as the mirror image of the other. More formally, two sets of points are called congruent if, and only if, one can be transformed into the other by an isometery, i.e., a combination of rigid motions, namely translations, rotations and reflections. This means that either object can be repositioned and reflected (but not re-sized) so as to coincide precisely with the other object. So two distinct plane figures on a piece of paper are congruent if we can cut them out and then match them up completely. Turning the paper over is permitted.
In elementary geometry the word congruent is often used as follows. The word equal is often used in place of congruent for these objects.

Two line segments are congruent if they have the same length.
Two angles are congruent if they have the same measure.
Two circles are congruent if they have the same diameter.
Two triangles are congruent if their corresponding sides are equal in length and their corresponding angles are equal in size.

Congruent Triangles
If two triangles are congruent they will have exactly the same three sides and exactly the same three angles.

The equal sides and angles may not be in the same position (if there is a turn or a flip), but they will be there.

SSS (side side side)
All three corresponding sides are equal in length.

SAS (side angle side)
A pair of corresponding sides and the included angle are equal.

ASA (angle side angle)
A pair of corresponding angles and the included side are equal.

AAS (angle angle side)
A pair of corresponding angles and a non-included side are equal.




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