The volume of the cylinder is
.. V = π*(d/2)^2*h
.. 3*(231 in^3) = (π/4)*d^2*(6 in) . . . . fill in the give numbers
.. (3*231*4)/(6π) in^2 = d^2 . . . . . . . . divide by the coeffient of d^2
.. d = √147.06 in ≈ 12.13 in . . . . . . . . take the square root
The diameter of the base would need to be about 12.13 inches.
