This document discusses the concept of CPCTC (Corresponding Parts of Congruent Triangles are Congruent). It states that once two triangles are proven to be congruent using SSS, SAS, ASA, AAS, or HL, then their corresponding sides and angles are also congruent due to CPCTC. An example proof is provided that uses CPCTC to show two angles are congruent after first showing the triangles are congruent using SAS.