Cody has a circular fish pond with a diameter of 6.4 feet around which he wants to put a sidewalk. He has enough concrete left over to cover an area of 65 square feet. Assuming the sidewalk is of uniform width, how wide can the sidewalk around the pond be?

Question

Cody has a circular fish pond with a diameter of 6.4 feet around which he wants to put a sidewalk.  He has enough concrete left over to cover an area of 65 square feet.  Assuming the sidewalk is of uniform width, how wide can the sidewalk around the pond be?

Henry · Answer

As = pi*r^2 = 65 Ft^2.=Area of sidewalk. r^2 = 20.69 r2 = 4.55 Ft. = Radius of sidewalk. r1 = 6.4/2 = 3.2 Ft. = radius of pond. W = r2 - r1 = 4.55 - 3.2 = 1.35 Ft. = Width of sidewalk.