4.1: Side-Angle-Side Condition
Our next goal is to give conditions that guarantee congruence of two triangles.
One of such conditions is given in Axiom IV ; it states that if two pairs of sides of two triangles are equal, and the included angles are equal up to sign, then the triangles are congruent. This axiom is also called side- angle-side congruence condition, or briefly, SAS congruence condition.