Note Use $\pi=\frac{22}{7}$, unless stated otherwise.
A conical tent is $10 \mathrm{~m}$ high and the radius of its base is $24 \mathrm{~m}$. Find the slant height of the tent. If the cost of $1 \mathrm{~m}^{2}$ canvas is $₹ 70$, find the cost of canvas required to make the tent.
Radius of the conical tent, r = 24 m
Height of the conical tent, h = 10 m
$\therefore$ Slant height of the conical tent, $l=\sqrt{r^{2}+h^{2}}=\sqrt{24^{2}+10^{2}}=\sqrt{576+100}=\sqrt{676}=26 \mathrm{~m}$
Curved surface area of the conical tent $=\pi r l=\frac{22}{7} \times 24 \times 26 \mathrm{~m}^{2}$
The cost of 1 m2 canvas is ₹ 70.
∴ Cost of canvas required to make the tent
= Curved surface area of the conical tent × ₹ 70
$=\frac{22}{7} \times 24 \times 26 \times 70$
= ₹ 1,37,280
Thus, the cost of canvas required to make the tent is ₹ 1,37,280.