Template:Unit of length 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 1 E+1 m (exponential notation) — meaning 10 × 1 m.
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 seldom encountered SI prefix: hecto- in hectopascal (hPa). The volumetric form (see below) cubic decametre is convenient for describing large volumes of water such as in rivers and lakes.
- For surface the square decametre (dam2) is a common unit, be it by the name are (a). The are is a measurement of area the size of 1 decametre by 1 decametre — the square decametre — 10 metres by 10 metres, equalling 100 square metres (100 m2).
- For volumes the cubic decametre (dam3) is also used, 10 m by 10 m by 10 m equalling 1,000 cubic metres (1,000 m3).
- SI prefix
- Metric system
- For length: 1 E+1 m and Orders of magnitude (length)
- For surface: 1 E+2 m² and Orders of magnitude (area)
- For volume: 1 E+3 m³ and Orders of magnitude (volume)
- Conversion of units, for comparison with other units