Talk:Thales' theorem

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Surely it should be Thales's theroem or Thales Theorem...? Jmccann: I agree.

Jmccann: I know the Greek letters don't look good, I'll spiff it up if someone else doesn't get to it first.

http://www.bartleby.com/141/strunk.html#1
I quote: Form the possessive singular of nouns with 's. But, later, Exceptions are the possessives of ancient proper names in -es and -is.

Jmccann: As a James, I am always bugged when someone refers to my stuff as James' (as if James is the plural of Jame). I left it as is because there seem to be several links to it. Basically, I am not excited enough to get worked up about it. My vote is for Thales's theorem. I had never heard of an exception for ancient proper names before this.

I think "Thales' Theorem" is correct. The spelling, not the theorem. Although that looks pretty correct, too. -- ESP 17:26 14 Jul 2003 (UTC)
When it comes to theorems of Greeks whose names end with an -s, there are usually three varations: Thales' theorem, Thales's theorem, and Theorem of Thales. All three are generally seen as acceptable. Other examples: Menelaus, Pappus of Alexandria. --Tokek 12:05, 27 Feb 2005 (UTC)

Quote "Since the sum of the angles of a triangle is equal to two right angles, we have

   2γ + γ ′ = 180°"

How would 2y + y be equal to two right angles? Dilbert 01:12, 2 April 2006 (UTC)


Thank You! This is very helpful. 72.197.201.129 01:13, 16 May 2006 (UTC)

[edit] Thales' other theorem

Many of the interwiki links describe a different theorem, also attributed to Thales, proving that parallel lines intersecting a pair of intersecting lines create similar triangles. (See fr:Théorème de Thalès for probably the best explanation). What is this theorem called in English, and is there an article here about it? (There should be.) Rigadoun 20:49, 2 August 2006 (UTC)

The french page is very good !

[edit] Sacrifice of a bull

I added this. SmokeyTheCat 14:40, 19 April 2007 (UTC)

[edit] More on Thales' other theoreme

Could someone please add information about Thales' other attributed theorem, which is often stated as "parallel lines intersecting a pair of intersecting lines create similar triangles," or "when parallel lines are intersected by two or more lines lines, the corresponding segments in the parallel lines are proportional."

In the French Wikipedia, this other theoreme is called Thales' Reciprocal Theoreme, and in the Spanish Wikipedia it's called Thales' FIRST theoreme.

Thanks!