Question 960161
In trig working with degrees, pi is 180 degrees, therefore
-3pi/7 = (-3*180) / 7 = -540 / 7 = -77.142857143 degrees
counter clockwise are positive angles and clockwise are negative angles
the related angle to -77.142857143 is (360 - 77.142857143) = 282.857142857 degrees
note that the angles 282.857142857 degrees and -77.142857143 degrees are in the fourth quadrant.