Question.
If the lateral surface of a cylinder is $94.2 \mathrm{~cm}^{2}$ and its height is $5 \mathrm{~cm}$, then find
(i) radius of its base
(ii) its volume.
[Use $\pi=3.14]$
(i) radius of its base
(ii) its volume.
[Use $\pi=3.14]$
Solution:
(i) Height $(h)$ of cylinder $=5 \mathrm{~cm}$
Let radius of cylinder be r.
CSA of cylinder $=94.2 \mathrm{~cm}^{2}$
$2 \pi r h=94.2 \mathrm{~cm}^{2}$
$(2 \times 3.14 \times r \times 5) \mathrm{cm}=94.2 \mathrm{~cm}^{2}$
$r=3 \mathrm{~cm}$
(ii) Volume of cylinder $=\pi r^{2} h$
$=\left(3.14 \times(3)^{2} \times 5\right) \mathrm{cm}^{3}$
$=141.3 \mathrm{~cm}^{3}$
(i) Height $(h)$ of cylinder $=5 \mathrm{~cm}$
Let radius of cylinder be r.
CSA of cylinder $=94.2 \mathrm{~cm}^{2}$
$2 \pi r h=94.2 \mathrm{~cm}^{2}$
$(2 \times 3.14 \times r \times 5) \mathrm{cm}=94.2 \mathrm{~cm}^{2}$
$r=3 \mathrm{~cm}$
(ii) Volume of cylinder $=\pi r^{2} h$
$=\left(3.14 \times(3)^{2} \times 5\right) \mathrm{cm}^{3}$
$=141.3 \mathrm{~cm}^{3}$
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