A shoe store owner is designing the layout of the displays in his store. The floor area for the store is 1,600 square feet. The owner wants to have circular displays for the shoes, each with a radius of 6 feet, and a 48-square-foot rectangular cashier's station in the corner. Customers should be able to easily walk around the shoe displays, so there must be at least a 4-foot walkway around each. The owner started drawing the layout shown. The distance between grid lines is 4 feet.