Definition talk:Angle

I can't decide which construction of angles makes the more sense: undirected angles with everything on the interval 0 to 180 degrees or directed angles on an open interval. Thoughts? --Cynic 03:04, 15 November 2008 (UTC)

Both, with an explanation as to the difference in concept between the two and the connection between them. Then any proofs which rely on either concept will have a ready-made framework to work in. --Matt Westwood 11:58, 15 November 2008 (UTC)

Page merge?
Might it be worth merging the different types of angles into this page as sub-pages, rather than have a different page for each one? Now I mention it, I'm not 100% sure it's a good thing to do - but what do you think? --Matt Westwood 13:02, 15 November 2008 (UTC)

Angles as equivalence classes
Is there a reference worthy approach somewhere that treats angles as equivalence classes? The equivalence relation being on $(\mathbb{R}^2)^3$. Likewise, for solid angles an equivalence relation on $(\mathbb{R}^3)^4$. --Jshflynn (talk) 17:50, 31 October 2012 (UTC)