Question

What is the volume of material required to make a hollow cylinder having inner and outer radius as 2 cm and 3 cm respectively and height as 14 cm?

• A. $572c{m}^3$
  
• B. $176c{m}^3$
  
• C. $396c{m}^3$
  
• D. $220c{m}^3$

Answer 1

The correct option is D

$220c{m}^3$

Given: Inner radius $\left(r_1\right)$ = 2 cm
Outer radius $\left(r_2\right)$ = 3 cm
Height $\left(h\right)$ = 14 cm

Volume of material required = Volume of hollow cylinder
= outer volume - inner volume
$=\pi r_2^{2}h-\pi r_1^{2}h$ [where $r_1$ and $r_2$ represents inner and outer radius respectively]

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

$=\frac{22}{7}\times 14\times [3^2-2^2]$

$=\frac{22}{7}\times 14\times 5$

$=220c{m}^3$