what is the basic unit of length
These larger and smaller units are called âderivedâ units. A) Length. The basic unit of length in the metric system is the meter (m). Common derived units are the centimeter (cm) (10-2 or 1/100 of a meter) and the millimeter (mm) (10-3 or 1/1000 of a meter). For measuring large distances, the kilometer (103 or 1000 meters) is often used. B) Volume.