A cylindrical riser is to be designed for a sand casting mold. The length of thecylinder is to be $2$ times its diameter. The casting is a square plate, each side $=30$cm and thickness h$=15$cm$.$If the metal is cast iron, and the mold constant in Chvorinov$$s rule $=2\mathrm{.}50$min$/$cm $^2.$

determine :

b$.$the size of the pattern for this casting by assuming only shrinkage allowance Find it by manufacturing methods