You can put this solution on YOUR website! angle in degrees is equal to angle in radians * 180 / pi
angle in radians is equal to angle in degrees * pi / 180.
examples:
360 degrees * pi / 180 = 2 * pi radians.
2 * pi radians * 180 / pi = 360 degrees.
your angle is 2 * pi / 3 radians.
multiply that by 180 / pi to get 120 degrees.
you can use your calculator to confirm these angles are equivalent.
set your calculator to degrees and get tan(120) = -1.732050808.
set your calculator to radians and get tan(2 * pi/3) = -1.732050808.
