Hello! :)
Sine, Cosine and Tangent are the main functions used in Trigonometry and are based on a Right-Angled Triangle. Before getting stuck into the functions, it helps to give a name to each side of a right triangle: "Opposite" is opposite to the angle θ "Adjacent" is adjacent (next to) to the angle θ.
This might help you: (:
I hope I helped and answered in time!
Good luck!
~ Destiny ^_^