Question

The inner circumference of a circular track is 220 m. The track is 7 m wide everywhere. Calculate the cost of putting a fence along the outer circle at the rate if rupee 2 per meter.

Answer 1

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Here is the solution:

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Find the inner radius:

Circumference = 2πr

2πr = 220 m

r = 220 ÷ 2π = 110/π = 35 cm

Find the outer radius:

Radius =  35 + 7 = 42 cm

Find the circumference:

Circumference = 2πr

Circumference = 2π (42 )

Circumference = 264 m

Find the cost of the fencing:

1 m² = Rs 2

264 m² = 264 x 2= Rs 528

Answer: The cost of the fencing is Rs 528

Answer 2

circumference of circle=2πr
220m=2*22/7*r
220*7/44=r
35=r
r of outer circle=35+7=42m
circumference of outer circle=2πr
=2*22/7*42
=264m
cost of fencing 1 meter=RS 2
cost of fencing 264m=2*264
=RS 528