The inner circumference of a circular track is 176 m. The track is 7 m wide. Calculate the:
(a) area of the track.
(b) cost of putting up a fence along the outer circle at the rate of 12 rupees per metre.
Answers
Area of the track is 1386m^21386m
2
and Cost of putting up a fence along the outer circle at the rate of rs 12 per metre is Rs.2640
Step-by-step explanation:
Step-by-step explanation:
Circumference of circle = 2 \pi r2π r
Inner circumference = 176 m
So, 2 \times \frac{22}{7} \times r = 1762×
7
22
×r=176
r = 176 \times \frac{7}{22 \times 2}r=176×
22×2
7
r = 28r=28
Inner radius r = 28 m
The track is 7 m wide .
Outer radius R = 28+7 = 35 m
Area of track = Outer area - Inner area = \pi R^2-\pi r^2=\frac{22}{7}(35^2-28^2)=1386m^2πR
2
−πr
2
=
7
22
(35
2
−28
2
)=1386m
2
Outer circumference = 2 \pi R = 2 \times \frac{22}{7} \times 35=220 m2π R=2×
7
22
×35=220m
Cost of fencing 1 m = Rs.12
Cost of fencing 220 m = 12 \times 220 = Rs.264012×220=Rs.2640
Hence Area of the track is 1386m^21386m
2
and Cost of putting up a fence along the outer circle at the rate of rs 12 per metre is Rs.2640
Step-by-step explanation:
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