reserve a, b, c, d, e for Complex;

theorem Th95: :: REAL_2'76
  c <> 0 & d<>0 & a/d=b/c implies a*c = b*d
proof
  assume that
A1: c<>0 and
A2: d<>0 and
A3: a/d=b/c;
  c*(a/d)=b by A1,A3,Lm3;
  then a*c/d=b by Lm8;
  hence thesis by A2,Lm3;
end;
