A decametre also dekametre (American spelling: dekameter, earlier decameter symbol dam) is a very rarely used unit of length in the metric system, equal to ten metres, the SI base unit of length. It can be written in scientific notation as (exponential notation) — meaning . This measure is included mostly for completeness. One practical use of the decameter is for altitude of geopotential heights (circumscribing equal pressure) in meteorology. Interestingly, meteorologists also use another… (More on Decametre)