I’ve learned about them in school, but I’ve never heard anyone say something is 8 decameters long or anything like that. I’m an American.

  • empireOfLove@lemmy.one
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    10 months ago

    They are “technically correct” measurements since they are a valid prefix, and could be used if you wanted. but they are very infrequently used in any industry. Since most of the time measurements are better served by higher precision (just using Meters) or need no precision at all over long distance (switch to kilometers), no need for excess measurement types unless necessary

      • empireOfLove@lemmy.one
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        10 months ago

        Well he asked about deca and hectometers, which are all larger-than meters.

        But the same kind of rules apply below the decimal point as above it. We have millimeters (0.001 extreme precision), centimeters (0.01 high precision), and meters (1 low-ish precision). Decimeters (0.1) exist but are rarely used since both meters and centimeters can get the same result. Micro meters and nanometers are also used more frequently, but it becomes industry specific when actually doing things that small.

      • Provoked Gamer@lemmy.ca
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        10 months ago

        Centimetres and meters are the two I use the most and see the most used, then kilometres at a close third.

  • vettnerk@lemmy.ml
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    10 months ago

    Valid, but rarely used, as it’s usually just as fast to say “two hundred meters” instead of “two hecto meters”.

    However, those prefixes have other (non-SI) uses. A hectare is common way of referring to a 100x100 meter area. And a decare is 10 ares, i.e. 0.1 hectare.

  • Im_old@lemmy.world
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    10 months ago

    For distance, no. Day to day we use mm, cm, m and km. But in more specialised settings (e.g. construction) I’ve seen sometimes decameters.

    For weight yes, grams, hectograms, kg, tons. Liquids is usually ml, cl, liters, hectoliters (not sure it’s spelt that way).

    In labs I’ve also seen also micro and nano of all three units.

    • Zippy@lemmy.world
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      10 months ago

      Use cubes for water. Short for cubic meter. That is 1 meter by 1 meter by 1 meter which is also exactly 1000 liters.

      This is one of the convenient metric parameters where they made an easy conversion allowing you to precisely use distance to calculate volume.

  • Blackmist@feddit.uk
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    10 months ago

    No, some measurements just aren’t used, even when they’d be a good fit.

    Like lengths. We never use anything above km. Even for things like space, we say “million km” rather than gigametre.

    The closest we come to hectometre is hectare, which is used for land area.

  • Grabbels@lemmy.world
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    10 months ago

    In The Netherlands we actually use “hectometerpaaltjes”, which translates to hectometer-signs. They are numbered signs placed on regional roads and highways every 100 meters, which is a hectometer. Although not a direct use of measurement, the term hectometer still is in active use this way.

  • Jeraxus@lemmy.sdf.org
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    10 months ago

    In France “hectare” (10 000m²) is used for fields and burning forest. Beside that deca or hectometers are never used

  • OptimusPhillip@lemmy.world
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    10 months ago

    As an American who has gotten very used to metric units in studying engineering, the general rule I picked up is that you typically only change units every three orders of magnitude. So 8 decameters would typically be expressed as 80 meters, maybe 0.08 kilometers. Decameters and hectometers are a thing, but they’re not common units. Even centimeters don’t see much use compared to millimeters.

    • Siegfried@lemmy.world
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      10 months ago

      We usually go for the 3 order rule, but in the case of areas and volumes, for dimensional reasons, dam and hm make it into the three order rule. Dm (or dam) is not common but dam^3 has some uses, the same goes for hm, hm is used for only special situations (like meassuring train distances), but hm^2 is almost globally used for big chunks of land. Also, with hm^2, we always keep the unit, so for example, Parque Nacional Iguazú in Argentina has 67620 hm^2 (also ha or hectarea).

      I’m also an engineer and I generally despise imperial units, but I have to say that inchs are pretty handy and the 1 in = 25,4000… mm relation is pretty neat

    • Cralder@feddit.nu
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      10 months ago

      That might be true for science but in everyday use centimeters, hektograms and the like are more common

  • dQw4w9WgXcQ@lemm.ee
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    10 months ago

    From my experience in Norway, these are typical in context of daily speech:

    Weight (gram): tonne (a substitute name for Mg (Mega)), kg, hg, g, mg, μg (mostly in medicine)

    Distance (meter): mil (10 km), km, m, dm (kinda rare), cm, mm

    Volume (liter): l, dl, cl, ml

    In my experience, the deca-predix is very rarely used. Most of the missing prefixes are just substituted for numbers, i.e. saying “a thousand kilometers” is much more common that “a megameter”. Of course, this differs depending on context, as a lot of the prefixes become more common within scientific fields where the sizes are common.

    On a separate note, even the numbers can be a bit inconsistent. It has bothered me that it’s often common to say “a thousand milliard” instead of “one billion” (also note that we use the long scale).

  • Siegfried@lemmy.world
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    10 months ago

    It depends on the situation, sometimes they are really handy but most of the time we stick to kilo, centi and mili.

    Where i live, Hecto (100x) is used, for example to measure distances and areas for big properties. 1 hectometro equalls 100 m, or 1 hectarea (hm^2) equals 10000 m^2.

    Also, it is widely use for pressure, cause 1 atm is 1013 hPa

    Decameters are used but for special situations, like quantifying natural gas consumption

  • bookmeat@lemm.ee
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    10 months ago

    Yes, they are used, but typically in specialized applications which is why you don’t see them every day.

  • Nerd02@lemmy.basedcount.com
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    10 months ago

    In Italy we use hectograms (“ettogrammi”, “etti” for short) in day to day life when buying groceries. You don’t ask for 200 grams of ham, you just ask for 2 etti.

    • zipzoopaboop@lemmynsfw.com
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      10 months ago

      Thinking how I always order deli meat in units of 100 grams, feels dumb we don’t do that in Canada too

      • Nerd02@lemmy.basedcount.com
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        10 months ago

        Yeah I don’t think it’s very common elsewhere. Right over the border with France they were already saying “200 grams de jambon”.

        But I think it’s convenient. Small number make brain hurt less, brain no need to think.

  • space@lemmy.dbzer0.com
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    10 months ago

    In Romania we use them for measuring areas. An “ar” is 100m^2 or a square decameter, and a hectare is a 10000m^2 or a square hectometer.

    • lugal@lemmy.world
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      10 months ago

      In Germany we only use hectare. Ar is something you learn in school and never use.

  • jrubal1462@mander.xyz
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    10 months ago

    In America, I’ve seen nurses and diabetics use deciliters in reference to medication or concentration before.

    • PlutoniumAcid@lemmy.world
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      10 months ago

      Deci is 0.1 and that gets used frequently, deka is 10 and never gets used at all, except in Austria when grocery shopping at the deli counter. 🤷

      Hekto is 100 and similarly never gets used, not even by Austrians.

    • yata@sh.itjust.works
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      10 months ago

      Deciliters are not infrequently used in recipes here as well. I’ve never seen decameters or hectometers used by anyone.