-128 degrees has a reference angle of what?

Question

It depends. Where zero is is arbritary. In polar coordinates, and geographical coordinates, zero is Upward (North), and clockwise is positive. In Tensors, zero often To the Right, and counterclockwise is positive. In HS algebra, zero angle is often along the x axis, and moving counterclockwise is positive. One has to keep in mind the decision on directions will impact vector cross product operations.