Question

If the lateral surface a cylinder is 94.2 cm 2 and its height is 5 cm, then find
I. Radius of its base and
II. Its volume

Answer 1

Hint: Compute radius from lateral surface area, proceed to find volume using the same radius.

Complete step-by-step answer:

Given, h= 5 cm
Let the radius be r cm, Now
(i) We know, Lateral/Curved Surface area=$2\pi rh$
Substituting all the values , we have
$
\Rightarrow 94.2c{m^2} = 2\pi rh \\
\Rightarrow 94.2c{m^2} = 2 \times 3.14 \times r \times 5cm \\
\Rightarrow r = 3cm \\
$

(ii) We know, Volume of cylinder= $\pi {r^2}h$
Substituting all the values along with value of r we found , we will have
$
\Rightarrow \pi {r^2}h = 3.14 \times 3 \times 3 \times 5 \\
= 141.2c{m^3} \\
$

Note: Formula of curved and total surface area, volume of general figures must be known for such
similar problems.