Question

A hollow garden roller, 63 cm wide with a girth of 440 cm, is made of 4 cm thick iron. Find the volume of the iron.

Answer 1

Here, R = Outer radius
          r = Inner radius
          t = Thickness = 4 cm
        w = Width = 63 cm
Girth = 440 cm = 2πR
\[R = \frac{440}{2 \times \frac{22}{7}} = 70cm\]
r = R − t = 70 cm − 4 cm = 66 cm
Volume of the iron = π (R² − r²) w = \[\frac{22}{7}\] − (70² − 66²) − (63) = 107712 cm³
Hence, volume of the iron is 107712 cm³.