Question

The radius of a circular ground is 35 m. A 3.5 m wide road runs around the boundary inside the ground. The region of the road between two radil inclined at 72° to each other needs to be repaired. Find the cost of repairing at the rate of 80/m2​

Answer 1

Answer:

Radius of the circular grass field is r

1

=35m

A 7m wide road runs round outside the field as shown in the figure.

So radius of the bigger circle is r

2

=35+7=42m

We can find the area of the road by subtracting the area of the grass field from the area of bigger circle.

So, area of the road =π(r

2

)

2

−π(r

1

)

2

=π(42)

2

−π(35)

2

=539π

=539×

7

22

=1694m

2

Answer 2

Step-by-step explanation:

Given The radius of a circular ground is 35 m. A 3.5 m wide road runs around the boundary inside the ground. The region of the road between two radil inclined at 72° to each other needs to be repaired. Find the cost of repairing at the rate of 80/m^2.

• So the radius of a circular ground is 35 m. So the track is 3.5 m wide.
• So the inner radius will be 35 – 3.5 = 31.5 m
• So the angle inclined will be theta = 72 degree.
• So the region will be outer ground – inner ground.
•                              =  π r^2 theta / 360 - π r^2 theta / 360
•                                        π (35)^2 x 72/360 – π (31.5)^2 x 72 / 360
•                                         π x 72 / 360 [ (35)^2 – (31.5)^2]
•                                                     = 146.17 sq m
• Now repairing cost will be area x 80
•                                           = 146.167 x 80
•                                           = Rs 11693.36

Reference link will be

https://brainly.in/question/26998824