#67:
radius is 2.1 ft
height is 4 feet
Area of base is pi*r^2 = 3.14(2.1 ft)^2 = 13.847
Volume is base times height: 13.847 sq ft times 4 feet = 55.3896
Your end result cannot be more accurate than one decimal place (which is what you have in the radius). Thus, round off your answer to 55.4 cubic feet.