Question

The curved surface area of a cylinder is $$ 1320 cm^2 $$ and its base has diameter 21 cm . find the volume of the cylinder.

Answer 1

Given: Diameter of cylinder (d) $$=21\space\mathrm{cm}$$

$$\Rightarrow$$ Radius of cylinder (r) $$=\dfrac{d}{2}=\dfrac{21}{2}=10.5\space\mathrm{cm}$$

Curved Surface area of cylinder $$=1320\space\mathrm{cm^2}$$

$$\Rightarrow 2\pi rh=1320$$

$$\Rightarrow 2\times\dfrac{22}{7}\times10.5\times h=1320$$

$$\Rightarrow h=1320\times\dfrac{1}{2}\times\dfrac{7}{22}\times\dfrac{1}{10.5}$$

$$\Rightarrow h=20\space\mathrm{cm}$$

Now, Volume of cylinder $$=\pi r^2h=\dfrac{22}{7}\times(10.5)^2\times20=6930\space\mathrm{cm^3}$$