A certain number of metallic cones each of radius 2 cm and height 3 cm are melted and recast in a solid sphere of radius 6 cm. Find the number of cones.

Radius of each cone (r) = 2 cm Height of cone (h) = 3 cm. Let the number of cones required to be recast into a solid sphere of radius (R) = 6 cm be n. n × Volume of each cone = Volume of sphere. On dividing both sides by π and multiplying by 3, Hence, the number of cones required to make a solid sphere of radius 4 cm are 72.