Additional dimensions also give you new ways to define angles. 2D: axis-axis (a-a) 3D: a-a, plane-axis (p-a) 4D: a-a, p-a, plane-plane (p-p), volume-axis

Additional dimensions also give you new ways to define angles. 2D: axis-axis (a-a) 3D: a-a, plane-axis (p-a) 4D: a-a, p-a, plane-plane (p-p), volume-axis (v-a) etc.