You wouldn't.
If you really wanted to you could, but it would be very impractical as a nickel is 1.95mm thick. So, there's roughly 512.8 nickels in a meter. So there are 512800 nickels in a kilometer. A nickel is 0.00000195km thick.
millimeters
Km is metric measure mile is US measure
Kilometer and centimeter
kilometer/ odometer
Millimeters.
cenemeters
Kilometer or mile
The thickness of a banana peel can be measured in millimeters (mm).
what is a thickness of a dime in metric measurements?
An appropriate metric unit to measure the Mississippi River would be kilometers (km) as it provides a more accurate representation of the river's length.
A micrometre.
There is only one metric system. The relevant units, within that system would be millimetres.