A metallic sphere of radius 21 cm is melted and then recast into smaller cones each with a radius of 7 cm, and a height of 3 cm. Find the number of cones obtained.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 252.
Volume of sphere = (4/3)πR3 = (4/3)× π × (21)3 = 12348π cm3
Volume of one cone = (1/3)πr2h = (1/3)× π × (72) × (3) = 49π cm3
Number of cones = (12348π)/(49π) = 252
Therefore, the number of cones obtained is 252.