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".

This article is about the SI prefix. For other uses, see Deca (disambiguation).

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 as a word on its own, 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. in the UK and Austria), "D" (e.g. in Germany), 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]
SI prefixes
Prefix Base 10 Decimal English word Adoption[nb 1]
Name Symbol Short scale Long scale
yotta- Y-  1024 1000000000000000000000000  septillion  quadrillion 1991
zetta- Z-  1021 1000000000000000000000  sextillion  trilliard 1991
exa- E-  1018 1000000000000000000  quintillion  trillion 1975
peta- P-  1015 1000000000000000  quadrillion  billiard 1975
tera- T-  1012 1000000000000  trillion  billion 1960
giga- G-  109 1000000000  billion  milliard 1960
mega- M-  106 1000000  million 1873
kilo- k-  103 1000  thousand 1795
hecto- h-  102 100  hundred 1795
deca- da-  101 10  ten 1795
 100 1  one –
deci- d-  10−1 0.1  tenth 1795
centi- c-  10−2 0.01  hundredth 1795
milli- m-  10−3 0.001  thousandth 1795
micro- μ-  10−6 0.000001  millionth 1873
nano- n-  10−9 0.000000001  billionth  milliardth 1960
pico- p-  10−12 0.000000000001  trillionth  billionth 1960
femto- f-  10−15 0.000000000000001  quadrillionth  billiardth 1964
atto- a-  10−18 0.000000000000000001  quintillionth  trillionth 1964
zepto- z-  10−21 0.000000000000000000001  sextillionth  trilliardth 1991
yocto- y-  10−24  0.000000000000000000000001  septillionth  quadrillionth 1991
  1. Prefixes adopted before 1960 already existed before SI. The introduction of the CGS system was in 1873.

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. http://channel.nationalgeographic.com/channel/content/kingdom-of-the-blue-whale-3302/blue-whale-facts/#/compare/length
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