Question

Find the total surface area of a hollow cylinder open at both ends, if its length is $12cm$, external diameter is $8cm$ and the thickness is $2cm$.

Answer 1

Given for the hollow cylinder with open at both ends, length is $h=12cm$, external diameter is $8cm$ and the thickness is $2cm.$

Then external radius is $r_1=4$ cm and internal radius is$r_2=4-2=2$ cm.

Now the total surface area of the hollow cylinder will be,

$=2\times \pi \times (r_1-r_2)\times h$

$=2\times \pi \times (4-2)\times 12$

$=48\pi$ cm${}^2$.