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This geometry math tutorial from NutshellMath offers homework help on proving two triangles are congruent. Two-column proofs of congruency are one of the most important aspects of geometry, and this tutorial introduces the five methods of proving the congruency of two triangles.


The first method is the Side-Side-Side Postulate (SSS), which states that two triangles with all three corresponding sides congruent are congruent triangles. The second method is the Side-Angle-Side Postulate (SAS), which states that two triangles are congruent if it can be shows that two corresponding sides and the included angle are congruent. The third method of proving two triangles congruent is the Angle-Side-Angle Postulate, which states that two triangles are congruent if it can be shown that two corresponding angles and the included side of the triangles can be proven congruent. The fourth method is the Angle-Angle-Side Theorem, which states that two triangles are congruent if two corresponding angles and one non-included side are congruent. The last method for proving two triangles congruent can only be used in right triangles. This method is the Hypotenuse-Leg Theorem, and states that two right triangles are congruent if one leg and the hypotenuse of one can be shown to be congruent to those of the other triangle.

These postulates can be used as reasoning for statements in two-column proofs. This tutorial offers a simple example of proving congruency through a two-column proof. The two-column method allows for making progressive statements of fact to reach a goal statement, which is then proven by the postulates presented.