Q:

Trigonometry Addition Thereom With Only one exact value?

Use the expression of $\sin(A+B)$ to evaluate $\sin 195$.
Do I use one exact value like $45+150$ or $60$ or is there another way?

A:

Here you go: $\sin 195° = -\sin 15° = -\sin(45-30)°$. After that you use standard formulas.

