Question

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Explanation:

Congruent figures can be mapped onto each other using rigid transformations (translations, reflections, rotations), which preserve size and shape. Figure 1 can be translated downwards to match the position of Figure 2, and side $\overline{ON}$ (a short side of Figure 1) corresponds to the short side $\overline{XZ}$ of Figure 2.

Answer:

The two figures are congruent because rigid transformations (translation) are used to map Figure 1 onto Figure 2.
Side corresponding to side $\overline{ON}$: $\boldsymbol{\overline{XZ}}$