Question

The curved surface area of a cone is 4070 cm² and its diameter is 70 cm. Find its slant height.

Answer 1

Diameter of the cone = 70 cm
i.e., radius, r = 35 cm
Curved surface area = 4070 cm²

$$\begin{gathered} \therefore \mathrm{\pi }rl=4070 \\ \Rightarrow \frac{22}{7}\times 35\times l=4070 \\ \Rightarrow l=\frac{4070\times 7}{22\times 35} \\ \Rightarrow l=37\mathrm{cm} \end{gathered}$$

Hence, slant height of the cone = 37 cm