Sydney is about 30 times smaller than Louisiana.

Louisiana is approximately 112,825 sq km, while Sydney (the 30 councils of metropolitan Sydney, without the Blue Mountains, Hawkesbury, Wollondilly and the Central Coast) is approximately 3,810 sq km, making Sydney 3.38% the size of Louisiana.
Tip: This to-scale comparison of Louisiana vs. Sydney uses the Mercator projection, which distorts the size of regions near the poles.
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