Unfortunately, your question is too broad, too vague, for someone to help you. Could you possibly share a problem in which you have the find the unknown angle measure?
Example: Supposing you had a right triangle with one of the acute interior angles equal to 30 degrees. If the hypotenuse is 5 and you are asked to find the length of the opposite side, you'd write this equation:
sin 30 = x/5. Multiplying both sides by 5, 5 sin 30 = x, or 5(1/2) = x, or x=2 1/2.