When a triangle is translated, the lengths of its sides do not change. Therefore, even after all the translations, the length of side \( X'Y' \) will still be the same as the length of side \( XY \).
Since the length of side \( XY \) is given as 10 units, the length of side \( X'Y' \) will also be:
\[ \text{Length of } X'Y' = 10 \text{ units} \]