the relationship between kilometers and meters is based on the metric system's decimal nature, where units are related by powers of 10. the prefix "kilo-" in the metric system means 1000, so a kilometer is literally 1000 meters.
this decimal-based system makes conversions between units straightforward - you simply multiply or divide by powers of 10, which is why converting meters to kilometers only requires dividing by 1000.
1公里＝1000米
1米 = 0.001千米
this system was developed during the french revolution in the late 18th century to create a universal, easy-to-use measurement system.