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Question
The inner circumference of a circular track is 264 m and the width of the track is 7 m. Find:
(i) the radius of the inner track.
(ii) the radius of the outer circumference.
(iii) the length of the outer circumference.
(iv) the cost of fencing the outer circumference at the rate of ₹50 per m.
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Solution
Inner circumference of the circular track = 264 m
(i) ∴ Inner radius (r) = `"C"/(2π)`
= `(264xx7)/(2xx22)=1848/44` = 42 cm
(ii) Width of the track = 7 m
∴ Outer radius (R) = 42 + 7 = 49 m
(iii) Outer circumference = 2πR
= `2xx22/7xx49` = 308 m
(iv) Rate of fencing = ₹50 per metre
∴ Total cost of fencing outer circumference = ₹50 × 308 = ₹15,400
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