Question

A heap of rice is in the form of a cone of diameter $9m$ and the height $3.5m$. Find the volume of the rice. How much canvas cloth is required to just cover the heap?

Answer 1

Given that, a heap of rice is in shape of a cone of height $h=3.5m$

Radius $r=\frac{9}{2}m=4.5m.$

Volume of heap =$\frac{1}{3}\pi r^{2}h=\frac{1}{3}\times \frac{22}{7}\times (4.5{)}^2\times 3.5m^3$

Volume $=74.25m^3$

Canvas cloth require to cover the help = $CSA$ of cone$=\pi rl$

Where $l=\sqrt{r^2+h^2}$

$l=\sqrt{(4.5{)}^2+(3.5{)}^2}=5.70m$

Now CSA $=\pi rl=\frac{22}{7}\times 4.5\times 5.70m^2$

CSA=$80.61m^2$