Question

The circumference of a circle is equal to the perimeter of a rectangle whose length and breadth are in ratio 9:7, respectively. If the area of the rectangle is 7623 cm2 , then find the radius of the circle.

A 56 cm Correct Answer Incorrect Answer
B 52.5 cm Correct Answer Incorrect Answer
C 53.5 cm Correct Answer Incorrect Answer
D 49 cm Correct Answer Incorrect Answer
E 50.5 cm Correct Answer Incorrect Answer

Solution

Let the length and breadth of the rectangle be 9x cm and 7x cm, respectively
According to the question,
9x × 7x = 7623
=> x2 = 7623/63 = 121
=> x = 11
Therefore, perimeter of the rectangle = 2 × (9x + 7x) = 352 cm
Let the radius of the circle be ‘r’ cm
According to the question,
2πr = 352
Or, r = 352 × (7/44) = 56 cm

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