Answer:
It is part of the argument.
Explanation:
AB + BC = AC.
So, the line segment EG , F lies on the line segment;
Therefore, by segment addition postulates we have below:
EG = EF + FG
By substitution AB=EF
EG = AB + FG
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Given: AB ≅ BC
BC ≅ EF
Prove: EG = AB + FG
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~lenvy~