Question

The volume of a sphere is 38808 $c{m}^3$. Find its radius and hence its surface area.

Answer 1

Sol:
Given that volume of a sphere is 38808 cm³ .

But volume of a sphere is (4/3)πr³ .

⇒ (4/3)πr³ = 38808

⇒ r³ = 38808 × 7/22 × 3/4

⇒ r³ = 441 × 7 × 3 = 9261

⇒ r³ = 7 × 3 × 7 × 3 × 7 × 3

⇒ r = 7 × 3 = 21

Surface area of sphere = 4πr² .

S = 4 × (22 /7) × 7 × 3 × 7 × 3

S = 5544 cm² .