Answer:
Becky, because her justification for the second statement should be "definition of supplementary angles" rather than "angle addition postulate."
Step-by-step explanation:
Becky completed the proof incorrectly because her justification for the second statement is not totally correct.
Angle addition postulate does not really apply here, as the sum of 2 angles may not give you exactly 180°.
However, the second statement, m<AKG + m<GKB = 180° and m<GKB + m<HKB = 180°, can be justified by the "Definition of Supplementary Angles".
The sum of supplementary angles = 180°.
Therefore, Becky completed the proof incorrectly.