Question

The circumference of a circle is equal to the perimeter of a rectangle whose length and breadth are in ratio 5:3, respectively. If the area of the rectangle is 1815 cm2 , then find the radius of the circle.

A 28 cm Correct Answer Incorrect Answer
B 23 cm Correct Answer Incorrect Answer
C 22 cm Correct Answer Incorrect Answer
D 20 cm Correct Answer Incorrect Answer
E 25 cm Correct Answer Incorrect Answer

Solution

Let the length and breadth of the rectangle be 5x cm and 3x cm, respectively
According to the question,
5x × 3x = 1815
=> x 2= 1815/15 = 121
=> x = 11
Therefore, perimeter of the rectangle = 2 × (5x + 3x) = 176 cm
Let the radius of the circle be ‘r’ cm
According to the question,
2πr = 176
Or, r = 176 × (7/44) = 28 cm

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