Answer:
(D) Reason3. congruent supplements theorem
Statement 4. ∠1≅∠2
Step-by-step explanation:
Given: ∠A is supplementary to ∠BCE.
To prove: ∠A≅∠1
Proof:
Statement Reason
1. ∠A is supplementary to ∠BCE. Given
2. ∠2 is supplementary to ∠BCE. From diagram
3. ∠A≅∠2 congruent supplements theorem
4. ∠1≅∠2 Vertical angles theorem
5. ∠A≅∠1 Transitive property of congruence
Thus, option D is correct.