Deca-

Deca (International spelling as used by the International Bureau of Weights and Measures;[1] symbol: da) or deka (American spelling[2]) is a decimal unit prefix in the metric system denoting a factor of ten. The term is derived from the Greek déka (δέκα) 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, deka (or deko) is common, and used in self-standing form, always meaning decagram. A runway number typically indicates its magnetic azimuth 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 (e.g., UK and Austria), D (e.g., Germany, Eastern Europe), 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.[3][4][5]

Examples:

  • The blue whale is approximately 30 metres or 3 decametres in length.[6]
PrefixBase 10 DecimalEnglish word Adoption[nb 1]Etymology
NameSymbolShort scaleLong scaleLanguageSource word
yottaY1024 1000000000000000000000000septillionquadrillion1991Latin eight[nb 2]
zettaZ1021 1000000000000000000000sextilliontrilliard1991Latinseven[nb 2]
exaE1018 1000000000000000000quintilliontrillion1975Greeksix
petaP1015 1000000000000000quadrillionbilliard1975Greekfive[nb 2]
teraT1012 1000000000000trillionbillion1960Greekfour,[nb 2] monster
gigaG109 1000000000billionmilliard1960Greekgiant
megaM106 1000000million1873Greekgreat
kilok103 1000thousand1795Greekthousand
hectoh102100 hundred1795Greekhundred
decada10110 ten1795Greekten
1001one
decid10−1 0.1tenth1795Latinten
centic10−2 0.01hundredth1795Latinhundred
millim10−3 0.001thousandth1795Latinthousand
microμ10−6 0.000001millionth1873Greeksmall
nanon10−9 0.000000001billionthmilliardth1960Greekdwarf
picop10−12 0.000000000001trillionthbillionth1960Spanishpeak, a little bit
femtof10−15 0.000000000000001quadrillionthbilliardth1964Danish fifteen, Fermi[nb 3]
attoa10−18 0.000000000000000001quintillionthtrillionth1964Danisheighteen
zeptoz10−21 0.000000000000000000001sextillionthtrilliardth1991Latinseven[nb 2]
yoctoy10−24 0.000000000000000000000001septillionthquadrillionth1991Latineight[nb 2]
  1. Prefixes adopted before 1960 already existed before SI. The introduction of the CGS system was in 1873.
  2. Part of the beginning of the prefix was modified from the word it was derived from, ex: "peta" (prefix) vs "penta" (source word).
  3. The fermi was introduced earlier with the symbol "fm", which prompted the reinterpretation of the "f" as a prefix to "m", with femto being derived from the Danish word femten due to its similarity.

See also

References

  1. Decimal multiples and submultiples of SI units, 2006, SI Brochure: The International System of Units (SI), 8th edition
  2. Guide for the Use of the International System of Units (SI), 1995, NIST Special Publication 811
  3. HP 48G Series – User's Guide (UG) (8 ed.). Hewlett-Packard. December 1994 [1993]. HP 00048-90126, (00048-90104). Retrieved 2015-09-06.
  4. HP 50g graphing calculator user's guide (UG) (1 ed.). Hewlett-Packard. 2006-04-01. HP F2229AA-90006. Retrieved 2015-10-10.
  5. HP Prime Graphing Calculator User Guide (UG) (PDF) (1 ed.). Hewlett-Packard Development Company, L.P. October 2014. HP 788996-001. Archived from the original (PDF) on 2014-09-03. Retrieved 2015-10-13.
  6. "National Geographic TV Shows, Specials & Documentaries".
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