you have a rotation angle of 360 °, take out the known values (360 ° -90 ° -144 ° = 126), 144 ° is part of a flat angle of 180 °, from 180 ° remove 144 and you have 36 °, they are opposite angles therefore the same. therefore 360 - 144 - 90 - 36 - 36 = 54.
