To determine if sides \( \overline{AC} \) and \( \overline{BC} \) are copies of side \( \overline{AB} \), Reza must check if they are the same length. The correct response that outlines this process is:
Reza must use his compass to measure side \( \overline{AB} \) to see if \( \overline{BC} \) and \( \overline{AC} \) are the same length.
This response is most straightforward and directly addresses the requirement to determine the congruence of the sides by measuring their lengths.