Reading this, something rings in my mind, but I cant find the room the ring comes from

I did this last year, but since I took an online class and therefor have no teacher,it's difficult to get the infos. The only thing I can remember is how to calculate sin,cos,tan using a scientific calculator

Mrs. Imconfused is having difficulty understanding the trigonometric concepts. She doesn't know when to use the Primary Trigonometric Ratios (sin, cos and tan), the Sine Law or the Cosine Law. She also needs clarification on what each one (primary trig ratios, sine law, cosine law) can be used to calculate. Provide an explanation that will help to solidify her understanding. Be sure to discuss what each one will calculate and how to decide which one to use. Explanations, diagrams, examples, formulas and mathematical terminology should all be included in your solution. Be thorough!