Question

A 4.2 m wide road surrounds a circular plot whose circumference is 176 m. Find the cost of paving the road at Rs 75 m ². 

Answer 1

Circumference of the plot = 176 m 

Radius of the circuIarplot = 

2πr = 176

r = `176 xx 7/22 xx 1/2`

r = 28 m

Radius of circular plot= 28 m 

Area of circular plot =π r² 

`= 22/7 xx 28 xx 28`

= 2464 m²

Area of circular plot= 2464 m² 

Radius of circular plot with surrounding road= R = ( 28 + 4.2) m= 32.2 m 

Area of circular plot with surrounding road = π R² 

`= 22/7 xx 32.2 xx 32.2`

= 3258.64 m²

Area of circular plot with surrounding road =3258.64 m² 

Area of road =Area of circular plot with surrounding road- Area of circular plot

= (3258.64 - 2464) m² 

= 794.64 m²

Area of road = 794.64 m² 

Cost of paving one sq m = Rs. 7 5 

Cost of paving the road =Rs (75 x 794.64) =Rs. 59,598 

Cost of paving the road =Rs. 59,598