How to draw the segment $[A,B] $ with only a ruler whose length is too short.

Question

Given the points $ A $ and $ B $ in the plane. I have been asked to draw the segment $ [A,B] $ with only a ruler whose length is much smaller than the length of the segment. I tried to construct a third point $ C $ between $ A $ and $ B $, but i can't figure out how to do.