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Topic: What's a 9,11,12,etc-sided figure called?
Replies: 38   Last Post: Dec 16, 2010 10:17 AM

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 John Conway Posts: 2,238 Registered: 12/3/04
Re: What's a 9,11,12,etc-sided figure called?"
Posted: Jan 20, 2004 1:13 PM

On 19 Jan 2004, Dr. Bluca wrote:

> A pentagon is a 5-sided polygon.
> A hexagon is a 6-sided polygon.
> A heptagon is a 7-sided polygon.
> Prefixes...
> tri- 3, quadri- 4, penta- 5, hexa- 6, hepta- 7, octa- 8, nona- 9,
> deca- 10

But "nona-" is really incorrect, the "official" prefix for 9
in this context being the Greek-derived one "ennea-". The sequence
continues up to 100 thus: hendeca, dodeca, triskaideca, tetrakaideca,...,
enneakaideca, icosa, icosikaihena, icosikaidi, icosikaitri,...
icosikaiennea, triaconta, triacontakaidi, ... , enneacontakaiennea, hecta.

Antreas Hatzipolakis and I once worked out a consistent continuation
to 100,000.

John Conway

Date Subject Author
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