Given line segments x and y, construct (using compass and straight edge) line segments having the following values:
x+y x-y x*y x%y The first two are immediate. I have proven that x%y is impossible if you are not given a reference length 1 (or some other reference length from which to construct 1). The problem is, prove or disprove that you construct x*y without using 1. (Constructing x*y and x%y _with_ 1 are pretty easy.) ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
