Athens is about 2.9 times bigger than Dayton.

Dayton is approximately 145 sq km, while Athens (map shows its 34 named neighbourhoods; the area covers the whole city) is approximately 412 sq km, making Athens 185% larger than Dayton.
Tip: This to-scale comparison of Dayton vs. Athens uses the Mercator projection, which distorts the size of regions near the poles.
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