Mensurationmedium · Past Paper
If the diameter of a sphere is decreased by 25%, by what percentage does its surface area decrease?
A43.75%
B25%
C50%
D56.25%
✓ Correct Answer: A — 43.75%
New radius = 0.75r. New area = 4π(0.75r)² = 0.5625 * Original Area. Decrease = 1 - 0.5625 = 43.75%.
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