Melbourne is about 25 times bigger than Washington.

Washington is approximately 158 sq km, while Melbourne (the 27 councils of metropolitan Melbourne, without the Yarra Ranges, Cardinia, Mornington Peninsula and Nillumbik) is approximately 3,915 sq km, making Melbourne 2,373% larger than Washington.
Tip: This to-scale comparison of Washington vs. Melbourne uses the Mercator projection, which distorts the size of regions near the poles.
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