Question

11. A circular track is 4.5 m wide. The inner and outer
circumferences are in the ratio 4:7. Find the
radius of the inner circle.
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Answer 1

Step-by-step explanation:

Let inner radius be r metre

therefore outerradius = r+4.5 m

now circumference = 2×pie×r

as the ratio is 4/7

2×π×r/2×π×(r+4.5) = 4/7

r/r + 4.5 = 4/7

7r = 4r + 18

3r = 18

therefor r = 6m