Question

a road 3.5 metre wide surrounds a circular plot whose circumference is 44 find the cost of painting the road at rupees 20 per metre square take Pi is equal to 22/7​

Answer 1

Step-by-step explanation:

Solution:-

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 = (44*7)/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 = πR² - πr²

= 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. 50 per sq m

Total cost of paving the road = 192.5 × 50

Total cost = Rs. 9625