Using a straightedge and a compass, it is possible to construct a copy of a segment. To do this, start by drawing a segment longer than the original with the straightedge.
To make the segments the same length, measure the original with a compass. Place the needle point on one endpoint, then, place the pencil at the other end.
The compass is now set to the correct length. After moving the compass to the new segment, mark where the end should be with the pencil.
This mark shows where to place the endpoint of the new segment. Placing the endpoint is the final step to copying the segment.