Question

A cylindrical pipe 20cm long has interior diameter equal to 12cm. If the thickness of the pipe is 1cm then whole surface of the pipe is?

Answer 1

Given,

$\sf Height \: = \: 20 \: cm \\ \\ \sf \: Diameter \: = \: 12 \: cm \: \\ \\ \sf \: Radius \: = \: \frac{1}{2} \: of \: Diameter \: so \: Radius \: = \: 6 \: cm$

$\boxed{ \sf \: Total\:Surface\:Area_{(Cylinder)}\:=\: 2\pi \: r \: (h + r)}$

Substituting the values, we get,

$\sf \: Total\:Surface\:Area_{(Cylinder)}\:=\:2 \: \times \: \frac{22}{7} \: \times 6(20 + 6)$

$\color{red}\sf{ \underline{\therefore \: Total \: surface \: area \: = \: 980.18 \: sq. \: cm}}$