The unit of length in the metric system is "meter". There are a number of equivalent units which are used under this system like millimeter, centimeter, kilometer. The aim of these equivalent units in metric system is to get a single unit for physical quantities. I am giving you the details through which they are linked with each other. For example, 1 millimeter is equal to 0.001 meter, 1 centimeter is equal to 0.01 meter, 1 decimeter is equal to 0.1 meter and 1 kilometer is equal to 1000 meters.

For example, if the length of rod is 1000 meters, then it can be also written as 1 kilometer.

For example, if the length of rod is 1000 meters, then it can be also written as 1 kilometer.