Philadelphia is 3.3 times larger than The Bronx (NYC borough).
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
Area: 112 km2 calculated
The Bronx is the northernmost of the five boroughs of New York City, in the U.S. state of New York. Coextensive with Bronx County, it was the last of the 62 counties of New York State to be incorporated. Wikipedia