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    Question

    Perimeter of a square and circumference of a circle are

    in the ratio 9:11, respectively. If area of the square is 81 cm2, then find the radius of the circle. (Take π = 22/7)
    A 7 cm Correct Answer Incorrect Answer
    B 6 cm Correct Answer Incorrect Answer
    C 8 cm Correct Answer Incorrect Answer
    D 9 cm Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the perimeter of the square and circumference of the circle be ‘9x’ cm and ‘11x’ cm, respectively. Area of square = a2 (Where ‘a’ is the side of the square) ATQ; 81 = a2 Or, a = 9 cm So, perimeter of the square = 9 × 4 = 36 cm So, circumference of circle = 36 × (11x/9x) = 44 cm Circumference of circle = 2πr (Where ‘r’ is the radius) So, 44 = 2 × (22/7) × r Or, r = 7 cm Therefore, radius of the circle is 7 cm.

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