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Question
There is a path of uniform width 7 m round and outside a circular garden of diameter 210 m. Find the area of the path.
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Solution
Diameter = 210 m
Radius of inner circle r2 = 105 m
Width = 7m
Radius of outer circle r1 = 105 + 7 = 112 m
∴ Area of path = `pir_1^2 - pir_2^2`
= `pi[r_1^2 - r_2^2]`
= `22/7(r_1 + r_2)(r_1 + r_2)`
= `22/7 (112 + 105)(112 - 105)`
= `22/7 xx 217 xx 7`
= 4774 m2
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