We need to solve for the radius
circumference = radius * 2 * PI
radius = circumference / (2*PI)
radius = 4.5 / ( 6.2831853072 )
radius = 0.7161972439 feet
Formula for cylinder volume:
Volume = π • r² • height
Volume = π • ( 0.7161972439)^2 * 12
Volume = PI * 0.5129384922 * 12
Volume 19.3373255857 cubic feet