There are 3 sides to a triangle. One side is 5" One side is 4" One side is 3" The phase angle (Theta) formula is: Tan-1 opposite over adjacent equals tan-1 4/3 How did they get the phase angle of 53.13 I am putting it in the calculator wrong. I am trying to get the phase of 6280(XL) over 5000(R) Is it tan-1 6280/5000 The answer key says it's .898 ??? I seem to be missing something.