Detroit is 3.3 times larger than Grand Rapids, Michigan.
Area: 117 km2 calculated
Grand Rapids is a city in the U.S. state of Michigan. It is located on the Grand River about 25 miles east of Lake Michigan. As of the 2010 census, the city population was 188,040. Wikipedia
Area: 383 km2 calculated
Detroit is the most populous city in the U.S. state of Michigan and the largest city on the United States-Canada border. It is the seat of Wayne County, the most populous county in the state. Wikipedia