Question

The radius and height of a cylinder are in the ratio $5:7$ and it's volume is $550c{m}^3.$ Find its radius.

Answer 1

Given $r:h=5:7$, where $r=$ radius and $h=$ height

let $r=5x$ and $h=7x$

volume of cylinder $=\pi r^{2}h$

$\Rightarrow 550=\frac{22}{7}\times 5x\times 5x\times 7x$

$\Rightarrow 550=550x^3$

$\Rightarrow x^3=1$

$\Rightarrow x=1$

So, radius $=5\times 1=5cm$, height $=7cm$