Using Chvorinov's rule as presented in the text with n = 2, calculate the dimensions of an effective riser for a casting that is a 2 in. by 4 in. by 6 in. rectangular plate. Assume that the casting and riser are not connected, except through a gate and runner, and that the riser is a cylinder of height/diameter ratio H/D = 1.5. The finished casting is what fraction of the combined weight of the riser and casting?