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Deca-
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<h2 id="si">SI</h2> <p>The prefix was a part of the original metric system in 1795. It is not in very common usage, although the deca<a href="/facts/Pascal_(unit)/Am1To2Qm">pascal</a> is occasionally used by <a href="/facts/Audiologist/Tjws1CnA">audiologists</a>. The deca<a href="/facts/Newton_(unit)/Ral9XgNl">newton</a> is also encountered occasionally, probably because it is an SI approximation of the <a href="/facts/Kilogram-force/RtMF3WhP">kilogram-force</a>. Its use is more common in <a href="/facts/Central_Europe/VdxzSbJz">Central Europe</a>. In German, Polish, Czech, Slovak, and Hungarian, <i>deka</i> (or <i>deko</i>) is common, and used in self-standing form, always meaning <i><a href="/facts/Kilogram/lU2zbPk8">decagram</a></i>. A <a href="/facts/Runway/EYy72SPJ">runway</a> number typically indicates its <a href="/facts/Compass/86MaeFXu">magnetic</a> <a href="/facts/Azimuth/kEyt9nJ3">azimuth</a> in <a href="/facts/Decadegree/f48Ns8SX">decadegrees</a>. </p><p>Before the symbol as an <a href="/facts/SI_prefix/Y2MzkaeL">SI prefix</a> was standardized as <i>da</i> with the introduction of the <a href="/facts/International_System_of_Units/S7YLglNz">International System of Units</a> in 1960, various other symbols were more common, such as <i>dk</i> (e.g., UK and Austria), <i>D</i> (e.g., Germany, Eastern Europe), and <i>Da</i>. For syntactical reasons, the <a href="/facts/HP_48G/FonQov9J">HP 48</a>, <a href="/facts/HP_49/50_series/CHJ2toxY">49, 50</a> series, as well as the <a href="/facts/HP_39gII/uKLfKyX0">HP 39gII</a> and <a href="/facts/HP_Prime/czJje3Ne">Prime</a> calculators use the unit prefix <i>D</i>.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a><a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> </p> <ul><li>1 decametre = 10 <a href="/facts/Metre/hPhzc1CV">metres</a></li> <li>1 decalitre = 10 <a href="/facts/Litre/QKwbQz8I">litres</a></li> <li>1 <a href="/facts/Decare/DPz2HDGr">decare</a> = 10 <a href="/facts/Hectare/DPz2HDGr">ares</a></li></ul> <p>Examples: </p> <ul><li>The <a href="/facts/Blue_whale/CSlRTeCf">blue whale</a> is approximately 30 metres or 3 decametres in length.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a></li></ul> <a href="/facts/Metric_prefix/Y2MzkaeL">SI prefixes</a><ul><li>v</li><li>t</li><li>e</li></ul><table><tbody><tr><th colspan="2">Prefix</th><th rowspan="2">Base 10</th><th rowspan="2"><a href="/facts/Decimal/7omfVNIM">Decimal</a></th><th rowspan="2">Adoption<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a></th></tr><tr><th>Name</th><th>Symbol</th></tr><tr><td>quetta</td><td>Q</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">1030</a></td><td>1000000000000000000000000000000</td><td rowspan="2">2022<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a></td></tr><tr><td>ronna</td><td>R</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">1027</a></td><td>1000000000000000000000000000</td></tr><tr><td>yotta</td><td>Y</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">1024</a></td><td>1000000000000000000000000</td><td rowspan="2">1991</td></tr><tr><td>zetta</td><td>Z</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">1021</a></td><td>1000000000000000000000</td></tr><tr><td>exa</td><td>E</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">1018</a></td><td>1000000000000000000</td><td rowspan="2">1975<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a></td></tr><tr><td>peta</td><td>P</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">1015</a></td><td>1000000000000000</td></tr><tr><td>tera</td><td>T</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">1012</a></td><td>1000000000000</td><td rowspan="2">1960</td></tr><tr><td><a href="/facts/Giga-/vdrYKueB">giga</a></td><td>G</td><td><a href="/facts/1,000,000,000/Ij1fl5Q7">109</a></td><td>1000000000</td></tr><tr><td><a href="/facts/Mega-/rk32jTkD">mega</a></td><td>M</td><td><a href="/facts/1,000,000/RMGVIm1j">106</a></td><td>1000000</td><td>1873</td></tr><tr><td><a href="/facts/Kilo-/akxTdXyp">kilo</a></td><td>k</td><td><a href="/facts/1000_(number)/b3LRnMBK">103</a></td><td>1000</td><td rowspan="3">1795</td></tr><tr><td><a href="/facts/Hecto-/gVT7dDuw">hecto</a></td><td>h</td><td><a href="/facts/100/G6ynN9mT">102</a></td><td>100</td></tr><tr><td>deca</td><td>da</td><td><a href="/facts/10/pqN3l0vm">101</a></td><td>10</td></tr><tr><td>—</td><td>—</td><td><a href="/facts/1/d6SoCnze">100</a></td><td>1</td><td>—</td></tr><tr><td><a href="/facts/Deci-/umQMMcHW">deci</a></td><td>d</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−1</a></td><td>0.1</td><td rowspan="3">1795</td></tr><tr><td><a href="/facts/Centi-/UhDg8BJG">centi</a></td><td>c</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−2</a></td><td>0.01</td></tr><tr><td><a href="/facts/Milli-/h1TVNfuW">milli</a></td><td>m</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−3</a></td><td>0.001</td></tr><tr><td><a href="/facts/Micro-/VXlL1EhM">micro</a></td><td>μ</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−6</a></td><td>0.000001</td><td>1873</td></tr><tr><td><a href="/facts/Nano-/hzbPWjMK">nano</a></td><td>n</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−9</a></td><td>0.000000001</td><td rowspan="2">1960</td></tr><tr><td>pico</td><td>p</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−12</a></td><td>0.000000000001</td></tr><tr><td>femto</td><td>f</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−15</a></td><td>0.000000000000001</td><td rowspan="2">1964</td></tr><tr><td>atto</td><td>a</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−18</a></td><td>0.000000000000000001</td></tr><tr><td>zepto</td><td>z</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−21</a></td><td>0.000000000000000000001</td><td rowspan="2">1991</td></tr><tr><td>yocto</td><td>y</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−24</a></td><td>0.000000000000000000000001</td></tr><tr><td>ronto</td><td>r</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−27</a></td><td>0.000000000000000000000000001</td><td rowspan="2">2022<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a></td></tr><tr><td>quecto</td><td>q</td><td><a href="/facts/Orders_of_magnitude_(numbers)/uu2o1hk2">10−30</a></td><td>0.000000000000000000000000000001</td></tr><tr><td colspan="5">Notes</td></tr></tbody></table> <h2 id="as-an-english-prefix">As an English prefix</h2> <p>The prefix is used in many words. </p> <h3>General</h3> <ul><li><a href="/facts/Decathlon/Cj6KBN7S">Decathlon</a>, a combined event in athletics consisting of ten track and field events.</li> <li><a href="/facts/Decennial/dXsq9vHt">Decennial</a>, ten-yearly or a celebration of ten years.</li></ul> <h3>Mathematics</h3> <ul><li><a href="/facts/Decimal/7omfVNIM">Decimal</a> based on the number ten.</li> <li><a href="/facts/Decagon/GdHnJjMK">Decagon</a> a plane figure with ten sides</li> <li><a href="/facts/Decahedron/HtQuJ1lx">Decahedron</a> a polyhedron with ten faces</li></ul> <h3>Chemistry</h3> <ul><li><a href="/facts/Decane/KPn6cJbz">Decane</a>, a hydrocarbon with 10 carbon atoms</li></ul> <h3>Biology</h3> <ul><li><a href="/facts/Decapoda/MycLb6mz">Decapoda</a>, an order of crustaceans with ten feet</li></ul> <h3>Religion</h3> <ul><li>The <a href="/facts/Decalogue/ITBbgDuP">Decalogue</a>, the <i>Ten Commandments</i></li></ul> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Metric_prefix/Y2MzkaeL">Metric prefix</a></li></ul> <h2 id="notes">Notes</h2> <h2 id="external-links">External links</h2> Look up <i>deca-</i> in Wiktionary, the free dictionary. <ul><li><a href="http://www.bipm.org">BIPM website</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Chambers Twentieth Century Dictionary. 1979. p. 332. <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>As used by the International Bureau of Weights and Measures.[2] <a href="/wiki/International_Bureau_of_Weights_and_Measures" target="_blank">/wiki/International_Bureau_of_Weights_and_Measures</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Guide for the Use of the International System of Units (SI), 1995, NIST Special Publication 811 <a href="http://physics.nist.gov/Pubs/SP811/sp811.html" target="_blank">http://physics.nist.gov/Pubs/SP811/sp811.html</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>HP 48G Series – User's Guide (UG) (8 ed.). Hewlett-Packard. December 1994 [1993]. HP 00048-90126, (00048-90104). Retrieved 2015-09-06. <a href="http://www.hpcalc.org/details.php?id=3937" target="_blank">http://www.hpcalc.org/details.php?id=3937</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>HP 50g graphing calculator user's guide (UG) (1 ed.). Hewlett-Packard. 2006-04-01. HP F2229AA-90006. Retrieved 2015-10-10. <a href="http://www.hpcalc.org/details.php?id=6512" target="_blank">http://www.hpcalc.org/details.php?id=6512</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>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. <a href="https://web.archive.org/web/20140903201341/http://h10032.www1.hp.com/ctg/Manual/c04119981.pdf" target="_blank">https://web.archive.org/web/20140903201341/http://h10032.www1.hp.com/ctg/Manual/c04119981.pdf</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>"National Geographic TV Shows, Specials & Documentaries". Archived from the original on March 6, 2009. <a href="https://web.archive.org/web/20090306112952/http://channel.nationalgeographic.com/channel/content/kingdom-of-the-blue-whale-3302/blue-whale-facts/#/compare/length" target="_blank">https://web.archive.org/web/20090306112952/http://channel.nationalgeographic.com/channel/content/kingdom-of-the-blue-whale-3302/blue-whale-facts/#/compare/length</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Prefixes adopted before 1960 already existed before SI. The introduction of the CGS system was in 1873. <a href="/wiki/Centimetre%E2%80%93gram%E2%80%93second_system_of_units" target="_blank">/wiki/Centimetre%E2%80%93gram%E2%80%93second_system_of_units</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>"On the extension of the range of SI prefixes". 18 November 2022. Retrieved 5 February 2023. <a href="https://www.bipm.org/en/cgpm-2022/resolution-3" target="_blank">https://www.bipm.org/en/cgpm-2022/resolution-3</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>"Metric (SI) Prefixes". NIST. <a href="https://www.nist.gov/pml/owm/metric-si-prefixes" target="_blank">https://www.nist.gov/pml/owm/metric-si-prefixes</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>"On the extension of the range of SI prefixes". 18 November 2022. Retrieved 5 February 2023. <a href="https://www.bipm.org/en/cgpm-2022/resolution-3" target="_blank">https://www.bipm.org/en/cgpm-2022/resolution-3</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> </ol>