reserve z,z1,z2 for Complex;
reserve r,x1,x2 for Real;
reserve p0,p,p1,p2,p3,q for Point of TOP-REAL 2;

theorem Th25:
  |.euc2cpx(p).|=|.p.|
proof
  |.p.| = sqrt ((p`1)^2+(p`2)^2) by JGRAPH_3:1;
  hence thesis by Th21;
end;
