Answer: A
Let the radius of the cone be \(r\) cm. \(\therefore \frac{1}{3} \pi r^2 \times 12 = 100\pi\) i.e., \(r^2 = \frac{100 \times 3}{12} = 25\) \(\therefore r = 5\) \(\therefore\) Slant height = \(\sqrt{12^2 + 5^2}\) cm \(= \sqrt{144 + 25}\) cm \(= \sqrt{169}\) cm \(= 13\) cm
Let the radius of the cone be \(r\) cm. \(\therefore \frac{1}{3} \pi r^2 \times 12 = 100\pi\) i.e., \(r^2 = \frac{100 \times 3}{12} = 25\) \(\therefore r = 5\) \(\therefore\) Slant height = \(\sqrt{12^2 + 5^2}\) cm \(= \sqrt{144 + 25}\) cm \(= \sqrt{169}\) cm \(= 13\) cm