Long straight wire/ magnetic field

[flame_m13]

this seems a very basic question when i write it, but i don't understand this: when you are dealing with a "long straight" wire, a wire that you cannot see the top or bottom of, then why do you consider the upper angle to be pi?
i know why the lower angle is considered 0; it is so small... this might be more of a math question.

if i need to post a picture so you can understand what I am talking about, please let me know.

 

[malty]

is pi 180º?? And isn't a long straight line 180º? Not sure if that's what you wanted the diagram would be nice to see.

Also isn't there a homework thread lol ;)

 

[flame_m13]

aw, i feel dumb. that makes sense... let us never speak of this again.