If the volume and surface area of a sphere are numerically the same, then find the volume (in cm3) of its semi − sphere. (correct to two places of decimals, use π = 3.14)
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e 56.52.
Volume of sphere = 4/3πr3
Surface area of sphere = 4πr2
Given:
4/3πr3 = 4πr2 ⇒ 1/3r3 = r2 ⇒ 1/3 r = 1 ⇒ r = 3
Volume of semi sphere = 2/3πr3 = 2/3 × 3.14 × 27 = 2/3 × 84.78 = 56.52 cm3