As a writer re-entering the world of secondary-school geometry after too long an absence, I seek guidance:
1) What is the current standard notation for -- -- the line through points A and B ? -- the ray from A through B ? -- the line segment connecting A and B ? -- the length of the segment connecting A and B?
2) How is "angle" defined? Here are some contemporary, conflicting examples taken from relatively recent secondary geometry texts:
Clemens & Clemens: An angle is made up of two rays with a common endpoint.
Lang & Murrow: Two rays starting from the same endpoint separate the plane into two regions. Each one of these regions will be called an angle determined by the rays.
Serra: An angle is two rays that share a common endpoint, provided that the two rays do not lie on the same line.
Thanks for any light you can shed on these questions.
(Note: If you're seeing this query for the second time, I apologize. I thought I had sent it before, but it didn't show up in my e-mail as a message from the Forum, so I'm trying again.)