Question

If the lateral surface of a cylinder is 94.2 cm${}^2$ and its height is 5 cm, then find
(i) radius of its base.
(ii) its volume(Use $\pi =3.14$).

• A. $r=3cm,volume=141.3c{m}^3$
• B. $r=2cm,volume=151.3c{m}^3$
• C. $r=5cm,volume=171c{m}^3$
• D. $r=3cm,volume=162c{m}^3$

Answer 1

The correct option is A $r=3cm,volume=141.3c{m}^3$

$LSA=94.2c{m}^2$

For cylinder $=$

$LSA=2nrh$

$\therefore 2\pi r\left(5\right)=94.2$

$2\times 3.14\times r\times 5=94.2$

$31.4\times r=94.2$

$r=3cm$

$\therefore$ radius of base $=3cm$

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

$=3.14\times (3{)}^2\times 5$

$=3.14\times 9\times 5$

$=3.14\times 45$

$=141.3c{m}^3$

$\therefore$ Volume of cylinder $=141.3c{m}^2$