Los Angeles is about 1.3 times smaller than Oahu.

Oahu is approximately 1,545 km² (597 sq mi), while Los Angeles (including the city proper only) is approximately 1,215 sq km, making Los Angeles 78.62% the size of Oahu.
Tip: This to-scale comparison of Oahu vs. Los Angeles uses the Mercator projection, which distorts the size of regions near the poles.
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