Final answer:
The Side-Angle-Side (SAS) postulate is used to determine if two triangles are congruent.
Step-by-step explanation:
The postulate used to determine if two triangles are equal (congruent) is the Side-Angle-Side (SAS) postulate. According to this postulate, if two sides and the included angle of one triangle are equal to the corresponding sides and included angle of another triangle, then the triangles are congruent. In other words, if two triangles have the same length for two sides and the same measure for one angle between them, then the triangles are congruent.