What are the metric units for measuring length?
The basic unit is the metre or meter. However, there are several other units within the metric system that are fractions of the meter and are sometimes more appropriate when defining the length of certain objects. These are the millimeter (mm) which is one-one thousandth of a meter (1,000 mm in a meter), the centimeter (cm) which is one-one hundredth of a meter (10 mm in a cm, 100 cm in a meter), the decimeter (dm) which is one tenth of a meter (100 mm in a dm, 10 cm in a dm, 10 dm in a meter), and the kilometer which is one thousand meters (1,000 meters in a kilometer). There are different terms because it is more useful to know km when measuring the length of china and mm when measuring the length of a lady-bug and so on.