Find the curved surface area of a cone with radius $7 \, cm$ and height $24 \, cm$. (in $cm^2$)

The radius of a sphere is decreased by $20 \% .$ By what per cent does its curved surface area decrease (in $\%$)?

Curved surface area of a cylinder $= \ldots \ldots \ldots$

$A$ conical tent is made from a piece of cloth with an area of $165 \, m^{2}$. The radius of the base of the tent is $5 \, m$.
$(i)$ If one student occupies an average of $\frac{5}{7} \, m^{2}$ of ground area,how many students can sit in the tent?
$(ii)$ Find the volume of the cone.

$A$ right triangle with sides $6 \, cm, 8 \, cm$ and $10 \, cm$ is revolved about the side $8 \, cm$. Find the volume and curved surface area of the cone so formed. $(\pi = 3.14)$

The total surface area of a cone whose radius is $\frac{r}{2}$ and slant height is $2l$ is