Question

The radius and height of a cone are in the ratio 4: 3. The area of the base is 154 cm². The area of the curved surface in $c{m}^2$

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Answer 1

$\frac{r}{h}$ = $\frac{4}{3}$

Base area = $\pi$$r^2=154$

$\Rightarrow r=7cm$

So, $h=\frac{3}{4}\times 7=\frac{21}{4}$

$\Rightarrow l=\sqrt{(h^2+r^2)}=\frac{35}{4}$

Hence, curved surface area = $\pi$$rl$

$\Rightarrow$ $\frac{22}{7}\times \left(7\right)\times \frac{35}{4}=192.5c{m}^2$