km kilometer 1000 meters
m meter 1 meter
dm decimeter 1/10 meter
cm centimeter 1/100 meter
mm millimeter 1/1000 meter
um micrometer 1/1000000 (one millionth) meter
nm nanometer 1/1000000000 (one billionth) meter
pm picometer 1/1000000000000 (one trillionth) meter
