Question

The circumference ofa circular plot is 220m. A 15m wide concrete track runs round outside the plot. Find the area of the track.

Answer 1

Answer:

4007.14 sq.m.

Step-by-step explanation:

Circumference of a circle = $2\pi r$

We are given that The circumference of a circular plot is 220 m.

So,  $220=2\pi r$

$220=2 \frac{22}{7} \times r$

$220\times \frac{7}{44} = r$

$35 = r$

Thus the radius of circular plot is 35 m.

Since we are given that 15 m wide concrete track runs round outside the plot.

Outer radius R = 35+15= 50 m

Area of the rack = Outer area - inner area

                           = $\pi (R^2-r^2)$

                           = $\frac{22}{7} \times (50^2-35^2)$

                           = $4007.14m^2$

Hence the area of the track is 4007.14 sq.m.

Answer 2

Answer:

4007.14

Step-by-step explanation:

Circumference of a circle = 2\pi r2πr

We are given that The circumference of a circular plot is 220 m.

So, 220=2\pi r220=2πr

220=2 \frac{22}{7} \times r220=2

7

22

×r

220\times \frac{7}{44} = r220×

44

7

=r

35 = r35=r

Thus the radius of circular plot is 35 m.

Since we are given that 15 m wide concrete track runs round outside the plot.

Outer radius R = 35+15= 50 m

Area of the rack = Outer area - inner area

= \pi (R^2-r^2)π(R

2

−r

2

)

= \frac{22}{7} \times (50^2-35^2)

7

22

×(50

2

−35

2

)

= 4007.14m^24007.14m

2

Hence the area of the track is 4007.14 sq.m.