1 kilometer (km) is equal to 1,000,000 millimeters (mm).
The prefix “kilo-” in the metric system signifies a factor of 1,000. Therefore, when you have 1 kilometer, you can convert it to millimeters by multiplying by 1,000:
1 kilometer = 1,000 meters 1 meter = 1,000 millimeters
So, 1 kilometer = 1,000 meters x 1,000 millimeters/meter = 1,000,000 millimeters.
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