A circular fountain with a radius of 7 m is encircled by a grass bed that is 3.5 m wide. Determine the ratio of the area of the graass bed to the area of the fountain.
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Correct answer: C
Explanation
The correct answer is option 3 i.e. 5:4.
Fountain area = πr2 = π × 72 = 49π
Outer radius = 7 + 3.5 = 10.5 m
Total area (fountain + grass) = π × 10.52 = 110.25π
Grass bed area = 110.25π – 49π = 61.25π
Grass : Fountain = 61.25π : 49π = 5 : 4