(-2,2), (4,-4). There are two common ways to attack this problem. The distance formula and Pythagorean theorem. I would use Pythagorean. make line segment cd the hypotenuse of a right triangle. legs would be 6 units and 6 units. a^2+b^2=c^2. 6^2+6^2=c^2. c^2=36+36. c^2=72. c=sq root of 72. c=8.5