Well, that would be imposible to solve. You are missing the radius. But if the radius was 5, then it would be simple. Ф=240.0 degreese = 4.19 radians. x=-2.50 y=-4.33 If the radius is different, then check out this website that me and my team has put togather. http://www.intmath.com/complex-numbers/convert-polar-rectangular-interactive.php