Question

The thickness of a hollow wooden cylinder is 2 cm. It is 35 cm long and its inner radius is 12 cm. Find the volume of the wood required to make the cylinder, assuming it is open at either end.

Answer 1

Inner radius, r = 12 cm

Thickness of cylinder = 2 cm

Outer radius = R = 12+2 = 14 cm

Height of cylinder, h = 35 cm

Volume of the wood = $\pi (R^2-r^2)h$

$=\frac{22}{7}\times \left[\right(14{)}^2-\left(12{)}^2\right]\times 35$

$=\frac{22}{7}\times (14+12)\times (14-12)\times 35$

$=22\times 26\times 2\times 5=5720$ $c{m}^3$