Colorado (USA) is 3,050 times larger than Round Rock, Texas.
Colorado is a U.S. state encompassing most of the Southern Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is part of the Western United States, the Southwestern United States, and the Mountain States. Wikipedia
Area: 88 km2 calculated
Round Rock is a city in the state of Texas within the Greater Austin, Texas metropolitan area and Williamson County. The 2013 census estimate places the population at 109,821. Wikipedia