Total piston displacement is given by the following formula P.D.=?DLN, where P.D. is the piston displacement in cubic inches, D is the diameter of bore

Total piston displacement is given by the following formula P.D.=?D²LN, where P.D. is the piston displacement in cubic inches, D is the diameter of bore of cylinder, L is the length of stroke in inches, and N is the number of cylinders.Find the diameter if the following are true.(a) PD. = 405 cu in., L = 4.7 in.(b) P.D. = 399.4 cu in.,N=7 L = 2 in., N = 6