Question

How many metres of cloth $5$m wide will be required to make a conical tent, the radius of the base is $7$m and whose height is $24$m?

Answer 1

$r=7m,h=24m,l=?$
$l^2=r^2+h^2=7^2+{24}^2=49+576=625$
$\therefore l=\sqrt{625}=25m$
Area of canvas used$=$CSA of conical tent
$\therefore$ CSA of a cone$=\pi rl=\frac{22}{7}\times 7m\times 25m=550m^2$
Area of canvas$=550m^2$
Length$\times$ width$=550m^2$
$\therefore$ length$=\frac{550m^2}{width}=\frac{550m^2}{5}=110m$
$\therefore$ Length of canvas used$=110$m.