Written Example Proof
Since the givens satisfy the three required inputs to SAS, students can see that they have completed the first part of the proof, and can now focus their attention on the second piece. The SAS Postulate proves that triangles are congruent, so they must now find a block in their toolkit that takes congruent triangles as an input. CPCTC fits that description and returns congruent segments or angles, the latter being the aim of the proof. Our students can now draw their proof as shown, certain that their logic is correct because all of the inputs and outputs of the blocks match. They know that they have reached the end because the final outgoing piece of information matches the prove statement in the original problem.