Origin of the Term Vertical AnglesDate: 04/04/2005 at 10:56:32 From: Neil Subject: Vertical angles Why do we call them "vertical angles" when many of them are "horizontal" (extending left and right)? Where did that name come from? Date: 04/04/2005 at 12:38:54 From: Doctor Peterson Subject: Re: Vertical angles Hi, Neil. They're called "vertical angles" because they share a "vertex". The confusion comes in because the Latin word "vertex" got into math by two different routes. A vertex originally meant the top of the head, or the summit of a hill. That led, on the one hand, to the idea of a corner of a figure, such as the apex of a pyramid, being called a vertex; and on the other hand, to anything at the top--like the highest point in the sky--being called vertical. So although vertical angles have nothing to do with being upright, and vertical lines have nothing to do with having a corner, we end up with the same word in both places. If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ Date: 04/04/2005 at 12:47:44 From: Neil Subject: Thank you (Vertical angles) Dear Dr. Peterson, Thank you so much for your answer to the "vertical" angle origin. I wish I had asked you that years ago. I will use your answer from now on when I am teaching about vertical angles. - Neil (in my 40th year of teaching secondary math) |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/dr.math/