Question

The external diameter of a cylindrical shaped iron pipe is $24cm$ and its length is $20cm$. If the thickness of the pipe is $1cm$, find the total surface area of the pipe(in $c{m}^2$).

Answer 1

We have,

Height of pipe $\left(h\right)=20cm$

External diameter $=25cm$

External radius $\left(R\right)=25/2=12.5cm$

Internal diameter $=25-(1+1)=23cm$

Internal radius $\left(r\right)=23/2=11.5cm$

Total surface area

$=2\pi (R+r)(R-r+h)$

$=2\pi (12.5+11.5)(12.5-11.5+20)$

$=2\pi \left(24\right)\left(21\right)$

$=1008\pi c{m}^2$

$=3168c{m}^2$

Hence, the total surface area of the cylinder $=3168c{m}^2$.