Question

The height of a cone is 24 cm and the diameter of its base is 14 cm. The curved surface area of the cone is
(a) 528 cm²
(b) 550 cm²
(c) 616 cm²
(d) 704 cm²

Answer 1

(b) 550 cm²

$$\begin{gathered} l=\sqrt{r^2+h^2} \\ =\sqrt{7^2+{24}^2} \\ =\sqrt{49+576} \\ =\sqrt{625} \\ =25\mathrm{cm} \\ \therefore \mathrm{Curved}\mathrm{surface}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{cone}=\mathrm{\pi }rl \\ =\frac{22}{7}\times 7\times 25 \\ =550{\mathrm{cm}}^2 \end{gathered}$$