Riverside, California is 4 times larger than Yonkers, New York.
Area: 208 km2 calculated
Riverside is a city in Riverside County, California, United States, located in the Inland Empire metropolitan area. Riverside is the county seat of the eponymous county and named for its location beside the Santa Ana River. Wikipedia
Area: 53 km2 calculated
Yonkers is the fourth most populous city in the U.S. state of New York, and the most populous city in Westchester County, with a population of 195,976. Wikipedia