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    Question

    If the radius of a sphere is decreased by 55%, then by

    what percent does its surface area decrease?
    A 72.06% Correct Answer Incorrect Answer
    B 79.75% Correct Answer Incorrect Answer
    C 68.9% Correct Answer Incorrect Answer
    D 72.96% Correct Answer Incorrect Answer

    Solution

    Let the radius of the sphere = 100 Area of sphere = 4π ×10000 When the radius decreased by 55% So, radius =45 Then area = 4π×45×45= 4π×2025 Decreased surface area = 10000-2025=7975 Percent of decrease = (7975/10000) ×100 =79.75%

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