Hayward is about 1.3 times smaller than Washington.

Washington is approximately 158 sq km, while Hayward (map shows its 16 named neighbourhoods; the area covers the whole city) is approximately 119 sq km, making Hayward 74.96% the size of Washington.
Tip: This to-scale comparison of Washington vs. Hayward uses the Mercator projection, which distorts the size of regions near the poles.
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