At a zoo, the lion pen has a ring-shaped sidewalk around it. The outer 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 9 m.
a. What is the circumference of the lion pen, not including the sidewalk? Show all work
b. Find the approximate area of the sidewalk. Use 3.14 to approximate π. Show all work.