Ho Chi Minh City is about 3.8 times bigger than Riyadh.

Riyadh (map shows its 9 named neighbourhoods; the area covers the whole city) is approximately 1,798 sq km, while Ho Chi Minh City is approximately 6,773 sq km, making Ho Chi Minh City 277% larger than Riyadh.
Tip: This to-scale comparison of Riyadh vs. Ho Chi Minh City uses the Mercator projection, which distorts the size of regions near the poles.
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