A solid metallic ball of radius 9 cm is melted and recast in to a right circular cylinder of double the radius of the ball. The curved surface area of the cylinder is :
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Correct answer: A
Explanation
The correct answer is option 1 i.e. 108 π cm2.
Volume of ball = Volume of cylinder
⇒ (4/3)π(9)3 = π(18)2h
⇒ h = 3
Now CSA of cylinder = 2πrh
⇒ 2π(18)(3) = 108π