SOLUTION: A circular path has an external radius of 20 m and it is 1 m wide. Find the total cost of gravelling the path at N130 per m ^ 2 and fencing both sides of the path at N37.50 per met

Question 1203039: A circular path has an external radius of 20 m and it is 1 m wide. Find the total cost of gravelling the path at N130 per m ^ 2 and fencing both sides of the path at N37.50 per metre . Give your answer to the nearest N100.
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
external radius is 20m.
internal radiu is 19m.
area of 20m circle is pi * 20^2 = 400 * pi
area of 19m circle is pi * 19^2 = 361* pi
area of the path is 400 - 361 = 39 * pi
cost of graveling is N130 * 39 * pi = N15927.87475 = N15900.
circumference of 20m circle is 2 * pi * 20 = 40 * pi.
circumference of 19m circle is 2 * pi * 19 = 38 * pi.
cost of fencing is N37.50 * (40 * pi + 38 * pi) = 37.50 * 78 * pi = N9189.158512 = N9200.
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