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. Two triangles are congruent if their corresponding sides are
equal in length, and their corresponding angles are equal in measure.
Triangle Congruence
If triangle ABC is congruent to
triangle DEF, the relationship can be
written mathematically as:
In many cases it is sufficient to use one of the following results to
deduce the congruence of the two triangles.