Question

    The circumference of a circle is equal to the perimeter of a rectangle whose length and breadth are in ratio 7:5, respectively. If the area of the rectangle is 4235 cm2 , then find the radius of the circle.

    A 73.5 cm Correct Answer Incorrect Answer
    B 42 cm Correct Answer Incorrect Answer
    C 59.5 cm Correct Answer Incorrect Answer
    D 38.5 cm Correct Answer Incorrect Answer
    E 50.5 cm Correct Answer Incorrect Answer

    Solution

    Let the length and breadth of the rectangle be 7x cm and 5x cm, respectively According to the question, 7x × 5x = 4235 => x2 = 4235/35 = 121 => x = 11 Therefore, perimeter of the rectangle = 2 × (7x + 5x) = 264 cm Let the radius of the circle be ‘r’ cm According to the question, 2πr = 264 Or, r = 264 × (7/44) = 42 cm

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