the diameter of a circular Park is 84 metre. on its outside there is 3.5 wide Road. find the cost of constructing the road at rupees 240 per metre square
Answers
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Answer:
=> Cost of constructing = 962.5 × 240
= ₹ 2,31,000
Step-by-step explanation:
Larger circle = Circle B
Smaller circle = Circle A
--------------------------------------------------------------------------------------------------------------=> Radius of Circle A = Diameter ÷ 2 = 84 ÷ 2 = 42 m
=> Area of Circle A = π × r^2
=> Area of Circle A = 22/7 × 42^2
=> Area of Circle A = 22/7 × 1764
=> Area of Circle A = 22 × 252
=> Area of Circle A = 5544 m^2
--------------------------------------------------------------------------------------------------------------=> Radius of Circle B = 42 + 3.5 = 45.5 m
=> Area of Circle B = π × r^2
=> Area of Circle B = 22/7 × (45.5)^2
=> Area of Circle B = 22/7 × 2070.25
=> Area of Circle B = 22 × 295.75
=> Area of Circle B = 6506.5 m^2
--------------------------------------------------------------------------------------------------------------
=> Area of road = Area of Circle B - Area of Circle A
=> Area of road = 6506.5 - 5544
=> Area of road = 962.5 m^2
--------------------------------------------------------------------------------------------------------------
=> Cost of constructing = Area × Cost/m
=> Cost of constructing = 962.5 × 240
=> Cost of constructing = ₹ 2,31,000