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
  |.cpx2euc(z).|=sqrt ((Re z)^2 + (Im z)^2)
proof
  (|[ Re z,Im z ]|)`1=Re z & (|[ Re z,Im z ]|)`2=Im z by EUCLID:52;
  hence thesis by JGRAPH_3:1;
end;
