Question

    The radius of a circle is increased by 20%. Find the

    percentage increase in the area of the circle.
    A 20% Correct Answer Incorrect Answer
    B 40% Correct Answer Incorrect Answer
    C 44% Correct Answer Incorrect Answer
    D 60% Correct Answer Incorrect Answer
    E 25% Correct Answer Incorrect Answer

    Solution

    The area of a circle is A = πr². If the radius increases by 20%,  the new radius is 1.2r. The new area is A' = π(1.2r)²  = 1.44πr². The percentage increase in area = (1.44 - 1) × 100 = 44%. Correct answer: c) 44%

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