Deca- or deka- is a decimal unit prefix
in the metric system, denoting a factor of ten. The term is derived from the
Greek deka, meaning “ten”. The prefix was a part of the original
metric system in 1795. It is not in very common usage, although the decapascal is
occasionally used by audiologists. The decanewton is also encountered
occasionally, probably because it is an SI approximation of the kilogram-force.
Its use is more common in Central Europe. In German, Polish, Czech, Slovak
and Hungarian, deca is common. A runway number typically indicates its heading
in decadegrees. Before the symbol as an SI prefix was
standardized as “da” with the introduction of the International System
of Units in 1960, various other symbols were more common, such as “dk”, “D”, and
“Da”. For syntactical reasons, the HP 48, 49, 50 series as well as the HP
39gII and Prime calculators use the unit prefix “D”.
1 decametre=10 metres 1 decalitre=10 litres
1 decare=10 ares Examples:
The blue whale is approximately 30 meters or 3 decameters in length.
^ The metric system was introduced in 1795 with several metric prefixes, of
which, however, only six were adopted as SI prefixes by the 11th CGPM conference
in 1960, whereas myria as well as double and demi were not adopted. In 1873,
micro and mega were recommended by the British Association for the Advancement
of Science. The other dates relate to recognition by a resolution of the CGPM.
See also Metric prefix
References ^ Guide for the Use of the International
System of Units, 1995, NIST Special Publication 811
^ HP 48G Series – User’s Guide. Hewlett-Packard. December 1994 .
HP 00048-90126,. Retrieved 2015-09-06. ^ HP 50g graphing calculator user’s
guide. Hewlett-Packard. 2006-04-01. HP F2229AA-90006. Retrieved 2015-10-10.
^ HP Prime Graphing Calculator User Guide. Hewlett-Packard Development
Company, L.P. October 2014. HP 788996-001. Retrieved 2015-10-13.
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