Practicing Success
The radius and height of a right circular cone are in the ratio 5 : 12. If its curved surface area is 816.4 cm², then volume of this cone is (taking \(\pi \) = 3.14): |
7,536 cm³ 2,512 cm³ 1,994 cm³ 1,884 cm³ |
2,512 cm³ |
If r = 5x, h = 12x ⇒ l = \(\sqrt {r^2 + h^2}\) = \(\sqrt {(5x)^2 +(12x)^2}\) = 13 x ⇒ C.S.A. = \(\pi \)rl ⇒ 816.4 = 3.14 × 5x × 13 x ⇒ x2 = 4 ⇒ x = 2 cm ⇒ So, r = 10 cm and h= 24 cm Volume = \(\frac{1}{3}\)\(\pi \)r2h = \(\frac{1}{3}\) × 3.14 × 100 × 24 = 2,512 cm3 |