Formula for angle between 2 lines
I can't figure out the yellow and red
parts of the solution to the problem below.
That picture at the bottom is mine. I drew it to try to help me but I am still
Yellow: Where did they get from? Why
do we care about this?
Red: If why is ?
Thanks a lot ---
Re: Formula for angle between 2 lines
Yellow - You have it marked. Your is nicely labeled. What would you label the next angle - continuing anti-clockwise? It begins on your blue ray and ends with the portion of the red ray extended through the origin.
Red - This is just a second case. If you changed to 160º, would give an acute angle?