Question

the cricumfernces of a circular park is 660m. A 7m wide path surrounds it. find its cost of fencing the outer boundary at the rate of rs. 60 per metre

Answer 1

2 × 22 / 7 × r = 660



r = 660 × 1 / 2 × 7 / 22

The track is 7 metre wide everywhere. therefore , the outer radius R is given by

R. = r + 7 => ( 105 + 7 ) metre = 112 metre


2 × 22 / 7 × R = Outer circumference



Outer circumference = 2 × 22 / 7 × 112 => 704 metres


Rate of fencing = Rs .60 per metre

total cost of fencing = ( Circumference × rate ) = Rs ( 704 × 60 )

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= Rs.42240
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