Lessee... OA is 1. OB is sqrt(2). OC is 2*sqrt(2). OD is the hypotenuse of triangle OCD, so it's equal to 2*sqrt(2)*sqrt(2), or 4. OE is OD+OC, or 4+2*sqrt(2). OF is easier to figure if we just pay attention to DE, which is just CD, which is OC. So DF is OC*sqrt(2), or 4. We've taken the previous OC...