The figure is made up of a cone and a cylinder.
Diameter = 16 ft
radius = 16รท2 = 8ft
Volume of the cone = 1/3bh
Volume of the cone =

Volume of the cone =

= 402.12
Volume of the cyclinder = bh
Volume of the cylinder =

Volume of the cylinder =

= 1206.37
Total = 402.12 + 1206.37 = 1608.49 cubic feet