Question

If volume of a cone is $1212c{m}^3$ and its height is $24cm$. Find the surface are of the cone $(\pi =\frac{22}{7})$

• A. $8081.41c{m}^2$
• B. $8881.41c{m}^2$
• C. $808.41c{m}^2$
• D. $881.41c{m}^2$

Answer 1

The correct option is A $8081.41c{m}^2$

Given that:

$h=24cm,$

Volume of cone $=1212c{m}^3$

$\pi r^2\frac{h}{3}=1212$

$r^2=\frac{1212\times 3\times 7}{22}$

$r^2=1156.90cm\Rightarrow r\approx 34cm$

Surface area of cone

$=\pi r(r+\sqrt{r^2+h^2})$

$=\frac{22}{7}\times 34(34+\sqrt{1157+576})$

$=\frac{22}{7}\times 34(34+41.62)$

$=8081.41c{m}^2.$