**The SSS congruence postulate states that if all three sides of one triangle are congruent to the corresponding sides of another triangle, the triangles themselves are congruent.** Triangles are congruent if, when one is superimposed on another, they match.

Several ways exist to prove triangles congruent. Aside from the SSS (or side-side-side) method, there are the SAS (side-angle-side), ASA (angle-side-angle), AAS (angle-angle-side) and HL (hypotenuse-leg) postulates. If triangles are congruent by any one of these, they are congruent. Congruent triangles have the same shape and size, though it is possible for one to be a mirror image of the other or rotated in some other way.