The reference angle of 4 is how many radians?

Answer 1

IF by 4 you mean 4 degrees, the reference angle is 4 degrees = 4pi/180= 4(3.14159)/180 = .07 radians

You can't mean 4 radians as the reference angle. Reference angles are less than pi/2 radians or less than 90 degrees. but if you meant the angle is 4 radians, then the reference angle is 4 - pi = about 0.86 radians = .86(57.3) = about 49 degrees

4 radians is in the 3rd quadrant