Seattle is about 2.1 times bigger than Tempe.

Tempe (map shows its 64 named neighbourhoods; the area covers the whole city) is approximately 104 sq km, while Seattle is approximately 217 sq km, making Seattle 110% larger than Tempe.
Tip: This to-scale comparison of Tempe vs. Seattle uses the Mercator projection, which distorts the size of regions near the poles.
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