Talk:CPCTC

The word "because" seems to reverse the proper roles of "if" and "then". The first paragraph seems to say that if the triangles are congruent, then so are the corresponding parts. But the word "because" appearing later appears to rely on a proposition saying that if the corresponding parts are congruent, then so are the triangles. Of course both are true, but they're separate propositions, and whoever wrote this appears not to appreciate that. Michael Hardy 02:53, 22 Mar 2005 (UTC)


 * I am the author. You have brought up valid points.  Because has different algebraic connotations that if and then.  I will revise the article to reflect proper terminology.  -- M e r o v i n g i a n  (t) (c) (w) 05:25, Mar 22, 2005 (UTC)

Another grammatical error... In the If...Then part, it says "If [congruent triangles], then the following conditions are true..." The use of "Conditions" is wrong, because Conditions refer to the If part of the statement. Rather, it should be "Statements." Alex144 (talk) 02:05, 7 August 2008 (UTC)


 * I've revised this per suggestion. Hazelorb (talk) 19:32, 20 June 2011 (UTC)

Also, is this really a theorem? The best I can find is from Hilbert saying it is the definition of congruent figures ("a 1-1 point correspondence such that all sides and angles are congruent"). Euclid didn't define congruent so it is hard to know from there... Hazelorb (talk) 19:50, 20 June 2011 (UTC) Edit: See - they call it a definition

This may or may not be a theorem depending on the definition one takes for congruence. If the definition is: two triangles are congruent if one is the image of the other under an isometry, then it is a theorem. If the definition is: two triangles are congruent if their corresponding sides and corresponding angles are congruent, CPCTC is a reiteration of the definition. Therefore it would not be a theorem in any standard US high school text. — Preceding unsigned comment added by Fthulin (talk • contribs) 19:32, 13 March 2014 (UTC)