Question

The volume of metal in a metallic cylinder pipe is $748c{m}^3$ , its length is $14cm$ and its external radius is $9cm$. Find its thickness.

Answer 1

Height of the cylinder $=14cm$

Let inner radius of the cylinder be $rcm$ and that of the outer cylinder be $Rcm$.

Therefore, volume of such cylinder $=\pi R^{2}h-\pi r^{2}h$

According to the question,

$\Rightarrow \pi h(R^2-r^2)=748$

$\Rightarrow \frac{22}{7}\times 14\times (9^2-r^2)=748$

$\Rightarrow 44\times 81-44r^2=748$

$\Rightarrow 44r^2=2816$

$\Rightarrow r^2=64$

$\Rightarrow r=8cm$

Thus, thickness of the cylinder is $=R-r=9-8=1cm$