Answer:
It is Becky, because her reasoning in step 2 fails to support her second assertion.
Step-by-step explanation:
Angles that sum to 180° are classified as supplementary angles.
The statement defining Supplementary Angles is the best justification for the second assertion made in Angie's proof, as opposed to Becky's Angle Addition Postulate.
Becky's postulate does not clarify why the two angles equal 180°. The Angle Addition Postulate states that the sum of two angles sharing a side may not necessarily equal 180°; they could sum to something less or more than 180°.
Thus, Becky made an error in her proof.
