When would be a situation where the intersection of two rays is NOT an angle?

Question

anonymous · Answer

when the slope of the two rays are equal?

turingtest · Answer

that was the only thing I could think too. Weird question though.

kainui · Answer

Is 180 degrees not an angle though?

msmr · Answer

When the slopes are the same, wouldn't they be the same ray?

anonymous · Answer

but different y-intercepts

kainui · Answer

I don't think so, it doesn't make sense to call them two separate rays if they are coming from the same location. That's like me shining a flashlight and saying they are two separate rays. On the other hand if they're both pointing directly at each other they have a different direction and are definitely intersecting... Meh weird question, wonder what its context is in haha.

msmr · Answer

Kainui: The question was one where you had to fill in whether the statement was "always, sometimes or never." The statement was "The intersection of two rays is an angle" and I filled in "Always," but I got the question wrong and I was trying to figure out why because I couldn't visualize anything where the intersection wouldn't make an angle...

mertsj · Answer

When the two rays are the same ray similar to a system of equations whose solution is every point on the line.

turingtest · Answer

here's a source that seems to agree with that sentiment http://www.mathopenref.com/intersection.html

kainui · Answer

I suppose they intersect at all points and therefore don't produce a single angle, but if you were to look at any one spot along where they run it would seem there is 180 degrees making them straight on. Obviously the answer isn't never and if the answer isn't always then it must be just sometimes and we'll have to live with it, even though it really doesn't make much sense why it should matter to make the distinction. If I were setting up an experiment where I needed two separate lasers pointing at something in such a way, I would probably call that 180 degrees, but whatever.

turingtest · Answer

I see where you're coming from Kainui, but an intersection seems to have to be singular by definition. A line segment can only intersect another line segment once. It's a technicality. In terms of much physics you could call it 180 for many purposes I'm sure.

mertsj · Answer

Did you ask your teacher?  Perhaps it was an error in grading.