Question

Amanda and Stephen wrote the following proofs to prove that vertical angles are congruent. Who is correct? Line segment NT intersects line segment MR forming four angles. Angles 1 and 3 are vertical angles. Angles 2 and 4 are vertical angles. Amanda's Proof Statement Justification ∠1 + ∠4 = 180° Definition of Supplementary Angles ∠3 + ∠4 = 180° Definition of Supplementary Angles ∠1 + ∠4 = ∠3 + ∠4 Transitive Property of Equality ∠1 ≅ ∠3 Subtraction Property of Equality Stephen's Proof Statement Justification ∠1 + ∠2 = 180° Definition of Supplementary Angles ∠2 + ∠3 = 180° Definition of Supplementary Angles ∠1 + ∠2 = ∠2 + ∠3 Transitive Property of Equality ∠1 ≅ ∠3 Subtraction Property of Equality

Answer 1

The answer:

the valid proof is Amanda's.

Statement Justification ∠1 + ∠4 = 180°
 Definition of Supplementary
Angles ∠3 + ∠4 = 180°
Definition of Supplementary Angles
∠1 + ∠4 = ∠3 + ∠4

Transitive Property of Equality ∠1 ≅ ∠3 

Answer 2

I agree with Nirina7