How do I determine what quadrant something is in if it lies

How do I determine what quadrant something is in if it lies on 90,180,270,360,etc...For instance cos3pi...How do I determine that that is in the 3rd quadrant...Thank You

see 0 to 90 lie in first quadrant 91 to 180 lie in second quadrant 181 to 270 lie in third quadrant and 271 to 260 lie in fourth quadrant each quadrant is of 90