Philadelphia is 2.1 times larger than Brooklyn (NYC borough).
Area: 180 km2 calculated
Population: 2,565,635 (2012)
Brooklyn is the most populous of New York City's five boroughs, with about 2.6 million people, as well as the second-largest in area. Wikipedia
Area: 370 km2 calculated
Population: 1,547,607 (2012)
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