Question

a road 3.5 m wide surround a circular plot circumference 44 find cost of paving road 20 per m
​

Answer 1

Answer:

Radius of plot=

2π

44

=

44

44

×7=7 m.

Area of road=π[(10.5)

2

−7

2

]=61.25×π

=192.42255 m

2

.

∴Cost Rs. =1924.22

Answer 2

Let the 'r' and 'R' be the radii of the inner and outer circle respectively. Circumference of the circle = 44 m

2πr = 44

2*22/7*r = 44

r = (447)/44

r = 7 m

So, the radius of the inner circle is 7 m

Width of the road = 3.5 m

So, radius of the outer circle

= 7+ 3.5

=10.5 m

Area of the road = 2πr² - 2πr²

= 22/7*10.5*10.5 - 22/7*7*7

= 346.5 - 154

Area of the road = 192.5 sq m

Cost of paving the road = Rs. 20 per sq m

Total cost of paving the road = 192.5 x 20

Total cost = Rs. 3850