The curved surface area of a cone is 4070 cm2
Question:

The curved surface area of a cone is $4070 \mathrm{~cm}^{2}$ and diameter is $70 \mathrm{~cm}$. What is its slant height?

Solution:

Diameter of the cone (d) = 70 cm

Radius of the cone $(\mathrm{r})=\mathrm{d}^{2}=35 \mathrm{~cm}$

Slant height of the cone (l) = ?

Now,

Curved Surface Area $=4070 \mathrm{~cm}^{2}$

$\Rightarrow \pi r \mid=4070$

Where, r = Radius of the cone

l = Slant height of the cone

Therefore πrl = 4070

⟹ 22/7 ∗ 35 ∗ l = 4070

$\Rightarrow \mathrm{l}=\frac{4070 * 7}{22 * 35}=37 \mathrm{~cm}$

Therefore slant height of the cone is 37 cm.