-
A rectangular block of metal has dimensions 21 cm, 77 cm and 24 cm. The block has been melted into a sphere. The radius of the sphere is (Take = 22/7)
-
- 21 cm
- 7 cm
- 14 cm
- 28 cm
- 21 cm
Correct Option: A
Volume of block = 21 × 77 × 24 cu. cm.
Let the radius of sphere be r cm, then
| πr³ = 21 × 77 × 24 | ||
| 3 |
| ⇒ r³ = | ||
| 4 × 22 |
= 21 × 7 × 3 × 3 × 7
= 3³ × 7³
⇒ r = 3 × 7 = 21 cm
