Imagine you were the manager of a national park with cheetahs. The cheetahs feed primarily on gazelles, while the gazelles eat grass. It takes an acre of grassland to feed one gazelle, and it takes ten gazelles to feed one cheetah. You have a maximum of ten cheetahs when the system is functioning optimally. You would like to increase the cheetah population because people pay money to see the cheetahs. How much total grassland do you need to double the cheetah population supported by this grassland?