Johannesburg is about 1.4 times bigger than Los Angeles.

Los Angeles (including the city proper only) is approximately 1,215 sq km, while Johannesburg is approximately 1,644 sq km, making Johannesburg 35% larger than Los Angeles.
Tip: This to-scale comparison of Los Angeles vs. Johannesburg uses the Mercator projection, which distorts the size of regions near the poles.
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