h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

If I wanted to write about polygons, which would be more correct/most useful to potential reader/clearest?

nonagon or enneagon? Has anyone ever used enneagon?
triskaidecagon or tridecagon or 13-gon or 13-sided polygon?
heptakaidecagon or heptadecagon or 17-gon or 17-sided polygon?

My favourites would be nonagon, tridecagon and heptadecagon, but certain sources seem to prefer the enne and sky contaminated versions...
vp

Nona- is Latin, Ennea- is Greek.

Do you say Pentagon and Hexagon? These are Greek, so you should be using Greek for 9 as well.

But surely more people have heard of the nonagon?

Quite right. I just checked two dictionaries and both listed nonagon but not enneagon. Neither has a word for a 13-sided shape. Mathematicians these days would be likely to say 13-gon, avoiding the problem of forming correct Greek words.

English has always used a mixture of Latin and Greek. Tele- is Greek for far. Skopeo is Greek for I see. Video is Latin for I see. So we have telescope and television, both meaning "far see", but one in Greek and the other a mixture.

Umm, am struggling for closure here... to clarify: To help keep us entertained in the long winter months ahead, my wife (who is a mathematician, and thought it sounded like fun) and I have agreed to translate a book about constructing regular polygons in our spare time. Original version is in Serbian, and the professor who wrote it fancies having an english version published...

After the last Serbian==>English book we translated together, which was an essay/novella on Bushido, we thought polygons would be relatively easy - no mis-translated koans which seem to have traveled from Japanese to English and then to Serbian to be translated back into English for instance. Nor did we need to spend an entire month of research and debate to get the title of this book right - its just called 'Regular Polygons'.

So I have to say, I was pretty alarmed to discover that the very names of the polygons themselves would be turn out to be an issue... In later chapters I will need to refer to 13-gons and 17-gons repeatedly, over and over again... A quick check with author has lead to use of nonagon so far for 9-gons, but not yet needed the others... 13-gon and 17-gon feel a bit slangy for a textbook, but as we are talking about paragraphs which might contain the word heptakaidecagon 5-10 times, I am worried its going to clutter the text somewhat.

Currently going to use tridecagon and heptadecagon, unless anyone here can confirm existance of 13-gon and 17-gon in formal maths writing?

vp

I suggest you use the names that they use on Wolfram Mathworld which is the definitive place for Maths on the Web:

http://mathworld.wolfram.com/Polygon.html

Ah ha, excellent link, thank you.
Wolfram it is vp.

The Springer Online Reference is quite serious too.

http://eom.springer.de/

It doesn't appear to answer this particular problem of the naming of polygons, though.

Oh, I just gave the link for completeness's sake. I hadn't actually checked that it answered the question, and it would have surprised me.

I might use 'enneagon' if a real word was needed, but to ease reading I would definitely tend to use '9-gon' or '13-gon' or whatever. Those fancy creations like sarantadyogon are not really words, are they? They just break the flow of reading.

I'd recommend sticking with nonagon, despite its odd etymology (from the Latin for "ninth" rather than "nine").

Interesting that mathworld bothers with digon - generally nobody lists it. I've seen it called a "bigon", but I thought "digon" better because it uses the Greek and it fits with the much more commonly used "dihedral". I have also had cause to read and write about monogons and nullgons.

As for 13-gon etc, a google search shows it in some books. I'm at a bit of a loss to say exactly where I've seen it, but I'd probably be more wary if I were writing for a general audience that for a mathematical one. Does the publisher not have a house style about this?

Just curious, but what are the names of polygons in Serbian?

triangle trougla
pentagon petougla
heptagon sedmougla
nonagon devetougla
tridecagon trinaestougla
heptadecagon sedamnaestougla

The words for 3,5,7,9,13 and 17 are tri, pet, sedam, devet, trinaest and sedamnaest respectively.

So its all fairly regular in the odd n-gon world (the a in sedam disappears all the time for some case related reason, and is apparently nothing to worry about), and rather spoilt by the word for square, which should really be cetirougla, but is in fact kvadrat.

Other polygons I am not so sure of, as I am the native english speaker of our partnership, and am yet to read any books on polygons in serbian other than this rather advanced one - the construction of even-numbered polygons being altogether too trivial to worry about obviously...

As for a publisher, not sure he has one of those yet - not really our problem as long as he is content to pay us anyway ... apart from having to make our own polygon naming decisions of course .

Thanks for all your help anyway guys - and Toy Box for the excellent timing of your submission of constructions with a ruler and compass entry.

vp

Glad to be of service

Ah, but what's the word for quadrilateral? A square is merely the regular four-sided figure.

To construct a regular polygon with an even number of sides, first construct the polygon with half that number of sides, then add in the extra vertices.

As I said, trivial - exactly what the book says, hence complete lack of even-sided polygon naming knowledge on my part. Curiously, as an chemist, I have rarely had the need to talk about polygons here in Serbia, until this book came along. In fact, I think the number of polygon related convos I have had down the pub in 3.5 years was no more than zero... I can tell you the highly serbian-sounding words for ICP-MS for instance (not without some grammatical errors mind), but poligoni were a bit of a closed book. Of course, cyclotomic equations were a completely closed book in any language before this translation came along... One lives and learns.

Sadly, the *general* quality of serbian-->english translations in this country is pretty poor (the grammars and styles are in fact, different, not something commonly acknowledged in the translation community ), and the technical stuff is even worse, so I guess the wife and I are pretty much the best bet this guy has.

vp

Oh yeah, loosely, its indukovane kuplovane plazme sa masenim detektorom

I presume Serbian is an Indo-European language on the west side of the un/ek divide, in which case, the word for one is probably una or ena or something like that, and the word for five is probably pfink.

jedan i pet

vp - I read your "obviously" as sarcastic, which I guess now it wasn't.

"(the grammars and styles are in fact, different, not something commonly acknowledged in the translation community )"

A peril of translation in general, I think. That's why you should only translate into languages you speak like a native - otherwise you can end up with something like the infamous badly translated Japanese electronics manuals.

Perilous indeed.

As for regular quadrilateral, as opposed to square, turns out to be cetvrougla in serbian, so it seems they sorted out their names much better than the english speaking mathematicians did....