Question

A solid is in the shape of a frustum of a cone . The diameter of the two circular ends 60 cm and 36 cm and the height is 9cm. find its volume.

Answer 1

vol. = 1/3 * pi*h(r^2+R^2+Rr)
      =1/3*22/7*9(900+1296+1080)
      =22*3*468
      =30888 cm^3

Answer 2

vol of frustum= pie/3 (r1 + r2)2 + (r1 + r2) + h
                      =22/7X3 (900 + 324 + 1080) + 48 +9
                      =22/21 (2304) +57
                       =2413.71 +57
                       =2470.71