Philadelphia is 3.2 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: 370 km2 calculated
Philadelphia is the largest city in the Commonwealth of Pennsylvania, the fifth-most-populous city in the United States, and the core of the sixth-largest metropolitan area in the country. Wikipedia