Question

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 rs 12 per metre
$(use\pi = 22by7)$

Answer 1

Radius of inner circle=176/2*7/22=28m
Radius of outer circle=35m
Area of path=22/7*35*35-22/7*28*28 =1386m^2
Total Cost=2×22/7×35×12=2640 rupees

Answer 2

Answer:

Area of the track is $1386m^2$ 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:

Circumference of circle = $2 \pi  r$

Inner circumference = 176 m

So, $2 \times \frac{22}{7} \times r = 176$

$r = 176 \times \frac{7}{22 \times 2}$

$r = 28$

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 = $\pi R^2-\pi r^2=\frac{22}{7}(35^2-28^2)=1386m^2$

Outer circumference =  $2 \pi  R = 2 \times \frac{22}{7} \times 35=220 m$

Cost of fencing 1 m = Rs.12

Cost of fencing 220 m = $12 \times 220 = Rs.2640$

Hence Area of the track is $1386m^2$ and Cost of putting up a fence along the outer circle at the rate of rs 12 per metre is Rs.2640