1. The problem asks which statement must be true about triangles that are similar. 2. By definition, similar triangles have the same shape but not necessarily the same size. 3. This means their corresponding angles are congruent (equal), but their corresponding sides are proportional, not necessarily congruent. 4. Therefore, the correct statement is (A): They have corresponding angles that are congruent. 5. Statements (B), (C), and (D) are false because similar triangles can be different sizes (B), are not all the same size (C), and their corresponding sides are proportional, not congruent (D). Final answer: (A) They have corresponding angles that are congruent.