Question

At a zoo, the lion pen has a ring-shaped sidewalk around it. The other edge of the sidewalk is a circle with a radius of 11 m. The inner edge of the sidewalk is a circle with a radius of 9m. (A) write and simplify an expression for the extra area of the sidewalk. (B) find the approximate area of the sidewalk. Use 3.14 to approximate J,L.

Answer 1

Diameter = 2r
6 = 2r r = 3 for the radius of the flowerbed
If we were to include the sidewalk around the bed, the diameter would stretch out another meter in both directions, meaning adding 2 meters to the diameter making the new diameter 6 + 2 = 8 and 8/2 = 4 so 4 = radius of the circle including the sidewalk. Find the area of the big circle and subtract the area of the smaller circle to find the area of the sidewalk.
Small circle = pi*3 squared.