Multiple choice

The surface area of a sphere is 616 square cm. If its radius is changed so that the area gets reduced by 75% ,then the radius becomes?

  1. 1.6 cm.

  2. 2.3 cm.

  3. 2.5 cm.

  4. 3.5 cm.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Surface area of sphere = 4πr² = 616, so r² = 616/(4π) = 154/π ≈ 49, giving r ≈ 7 cm. If area reduces by 75%, new area = 25% of 616 = 154. Then 4πR² = 154, so R² ≈ 12.25, R ≈ 3.5 cm. The answer matches option D.

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