SSC MTS 2 Aug 2019 Shift 3 Paper

h = 5 cm, r = 12 cm
Let the lateral height be l,
⇒ ${\mathrm{l}}^2+{\mathrm{r}}^2+{\mathrm{h}}^2$
⇒ ${\mathrm{l}}^2$ = 144 + 25 = 169
⇒ l = 13 cm
⇒ The curved surface area of the cone = $\mathrm{\pi }\times \mathrm{r}\times \mathrm{l}$
⇒ The curved surface area of the cone = $\mathrm{\pi }\times 12\times 13=156\mathrm{\pi }{\mathrm{cm}}^2$
∴ The curved surface area of the cone is $156\mathrm{\pi }$ ${\mathrm{cm}}^2$ .