How to calculate concrete volume of hopper for piling?

Top diameter = 1200 mm,  radius = 600 mm = 0.6 m

Bottom diameter = 125 mm, radius = 0.625 m

Hopper

Area of Top (A1)

= πr²

= 3.14 x 0.6 x 0.6

= 1.1304 m²

Area of Bottom (A2)

= πr²

= 3.14 x 0.625 x 0.625

= 0.0123 m²

Volume of Hopper =

= 0.2521 cubic meter