Las Vegas is 2.4 times larger than Dayton, Ohio.
Area: 149 km2 calculated
Population: 141,359 (2012)
Dayton is the sixth largest city in the U.S. state of Ohio and is the county seat of Montgomery County. Wikipedia
Area: 363 km2 calculated
Population: 596,424 (2012)
Las Vegas, officially the City of Las Vegas and often known as simply Vegas, is the most populous city in the state of Nevada and the county seat of Clark County. Wikipedia