Question

the diameter of a circular Garden is 42 metre on its outside there is a road 7 M wide find the cost of levelling the road @ rupees 1.20 per square metre

Answer 1

Diameter of garden = 42 m
Radius of garden = 21 m

Radius of outer circle = 21+7 = 28 m

Area of road = Area of outer circle - Area of garden
Area of road = pi *28^2 - pi *21^2
= pi ( 28^2 - 21^2)
= pi (28+21)(28-21)
= 22*49*7/7
= 22*49
= 1078 m^2

Cost of levelling = 1078 * 1.2
= 1293.6

Answer 2

d=42
R=21
so, area of garden= πr²
22÷7×21×21
22×63
1386

area along with road
r=21+7
r=28
area=22/7×28×28
2464
difference = 2464-1386
1078

road area=1078
1078×1.2
1293.6 rs