Answer:
The answer is A. Substitution
Step-by-step explanation:
Looking at the previous proofs, you can see that:
∠Y≅∠4
∠Z≅∠6
∠X + ∠4 + ∠6 = 180°
Statement 5 then replaces ∠4 and ∠6 with ∠Y and ∠Z, respectively. Replacing it means that it was substituted with the GIVEN values by the previous statements.
The best answer is the Substitution.
