A hollow cylindrical pipe is 21 dm long. It outer and inner diameters are 10cm and 6cm respectively. Find the volume of the copper used in making the pipe.

Explanation

Given : Height of cylindrical pipe is `21dm`

`h=21xx10=210cm`

Outer diameter, `D=10cm`

Outer Radius, `R=5cm`

Inner Diameter, `d=6cm`

So, Inner radius, `r=3cm`

Now, Volume of copper used in making the pipe = `pi(R^2-r^2)h`

`V=22/7(5^2-3^2)210`

...