Question

Need to find A and B, I already found C

Answer 1

I'm going to assume you've learn sin, cos, and tan. To find a you must do:
$sin^{ - 1} = \frac{a}{12}$
Once you find a, you can use the Pythagorean Theorem to find b:
${a}^{2} + {b}^{2} = {c}^{2}$
Or you can do:
$cos^{ - 1} = \frac{b}{12}$
You can find these functions on a scientific calculator. Let me now if you need more help.