Fill in the blanks to complete this proof of the Congruent Complements Theorem (Theorem 2-3). Ifnvo angles are complements ofthe same angle, then the angles are congruent. Given: Ll and L2 are complementary. L3 and Z-2 are complementary. Prove: Zl L3 See Problem 3, 1 2 3 Proof: Ll and Z-2 are complementary and L3 and L2 are complementary because it is given. By the definition of complementary angles, mi.-I + mL2= a. ? andmL3 + mL2= b. ? . Then mL1 + mL2 = mL3 + mL2 by the Transitive Property ofEquality. Subtract mL2 from each side. By the Subtraction Property of Equality, you getmL1 = C. ? .. ? , so Ll L3.