This document provides guidance on writing proofs to show that two triangles are congruent. It explains that a congruent triangle proof should include (1) marking given information on a diagram, (2) identifying the congruence theorem and additional information needed, and (3) writing statement reasons. An example proof is provided demonstrating these three steps, using the Side-Side-Side congruence theorem to prove triangles ABC and CBD are congruent. Common theorems that can be used in congruent triangle proofs are also listed.