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SSC MTS 2024 PYQ — Question 6

SSC MTS - 07/10/2024 - (12:30 PM - 2:30 PM) • Quantitative Aptitude • Q6

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The volume of the hemisphere is 486π cm3. If the radius is tripled, then what will be its curved surface area (in cm2)?

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Correct answer: B

Explanation

The correct answer is Option 2 i.e. 1458π.

Volume of hemisphere = 23πr3{2\over3} \pi r^3

⇒ 23πr3{2\over3} \pi r^3 = 486π

⇒ 23r3{2\over3} r^3 = 486

⇒ r3 = 729

⇒ r = 9 cm

If the radius tripled:

New radius: 3 × 9 = 27 cm

Curved surface area of a hemisphere = 2πr2

⇒ 2π(27)2 = 1458π cm2