Question

The volume of cylindrical pipe is $784{cm}^2$ and its height is $14cm$. If the external radius of the pipe is $9cm$, then find the thickness of pipe.

• A. $4.87cm$
• B. $1.86cm$
• C. $1.54cm$
• D. $1.44cm$

Answer 1

The correct option is A $4.87cm$

Dimensions of a pipe

Height $=h=14cm$

Radius = $r.cm$

Given,

Volume$=748c{m}^3$

$Pi\ast r^2\ast h=748$

$22/7\ast r^2\ast 14=748$

$r^2=(748\ast 7)/(22\ast 14)$

$r^2=17$

$r=\sqrt{1}7$

$r=4.12$

Given external radius $r=9cm$

Thickness of the pipe$=9-4.12=4.87cm$