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Question
A circular field of radius 105 m has a circular path of uniform width of 5 m along and inside its boundary. Find the area of the path.
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Solution

The radius of circular field, `r_1 = 105`m
Width of path = 50 m
∴ The radius of the inner circle, `r_2 = 105 - 5 = 100`m
Area of path = `pir_1^2 - pir_2^2`
= `22/7[(105)^2 - (100)^2]`
= `22/7(105 + 100)(105 - 100)`
= `22/7 xx 205 xx 5`
= `22550/7`m2
= `3221 3/7`m2
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