Answer:
Side ON is the name of the image of side DC.
Explanation:
According to the problem, figure PMNO is the image of figure ABCD. That means each vertex has a corresponding pair, that is, P with A, M with B, N with C, and O with D.
We apply the same logic to sides, if PMNO corresponds to ABCD, then each corresponding pair of sides would be
PM to AB.
MN to BC.
NO to CD.
Therefore, the image of side DC must be ON, because DC = CD and ON = NO.