you need a compass and a straightedge, then draw a line longer than the original line, after that put the sharp point of your compass on one end of the original line and open or close the compass so that the other point is on the other end of the original line. next keep the compass the same length and put the sharp point on one end of your longer line and use the pencil end to draw an arc that intersects the line. where the line intersects you will probably want to put a point. and the end where your sharp point was you will want a point also. the line segment will then be congruent to the original. hope this helps!
