Austin, Texas is 8.8 times larger than Fontana, California.
Area: 933 km2 calculated
Austin is the capital of Texas and the seat of Travis County. Located in Central Texas and the American Southwest, it is the 11th-most populous city in the United States of America and the fourth-most populous city in the state of Texas. Wikipedia
Area: 106 km2 calculated
Fontana is a city of 200,762 residents in San Bernardino County, California. Founded by Azariel Blanchard Miller in 1913, it remained essentially rural until World War II, when entrepreneur Henry J. Kaiser built a large steel mill in the area. Wikipedia