What is the argument of -5i? I have been stuck on this for a while!

Question

solomonzelman · Answer

argument of  -5i ?

anonymous · Answer

Yes.

solomonzelman · Answer

I haven't ever heard of such a concept in math -:(

anonymous · Answer

Okay :(

anonymous · Answer

argument i think is the same as the angle, yes?

myininaya · Answer

anonymous · Answer

|dw:1401672180125:dw|

anonymous · Answer

wow a celebrity!  hello!!

anonymous · Answer

you can see what the angle is directly from the picture
you have lots of choices because it is not unique

anonymous · Answer

I still really don't understand it. Could you explain it to me please in more depth?

myininaya · Answer

you need to find the angle between the initial ray and the terminal ray 
that is find this angle:
|dw:1401679079632:dw|

anonymous · Answer

Okay...I still don't know how to exactly get the answer though. It is confusing for me.

myininaya · Answer

you know that is a right angle?|dw:1401680681402:dw|