Pittsburgh is 3.1 times larger than Erie, Pennsylvania.
Area: 50 km2 calculated
Erie is a city located in northwestern Pennsylvania, United States. Named for the lake and the Native American tribe that resided along its southern shore, Erie is the state's fourth-largest city, with a population of 102,000. Wikipedia
Area: 153 km2 calculated
Pittsburgh is the seat of Allegheny County and with a population of 305,841 is the second-largest city in the U.S. state of Pennsylvania. With a metropolitan CSA population of 2,659,937, it is the largest in both the Ohio Valley and Appalachia and the 20th-largest in the U.S. Wikipedia