Formal proofs can be written to verify that two triangles are similar. In this topic, you have explored how to use the SSS Similarity Theorem, the SAS Similarity Theorem, and the AA Similarity Postulate to write a two-column proof for similar triangles. In addition, you also proved triangles similar using coordinate methods. It is important to remember that for similar triangles, corresponding angles must be congruent and corresponding sides must be proportional.