How is sine obtained in a right triangle? What about cosine?

If that doesn't make sense, draw a right triangle with leg lengths 5 and 12, and answer the following questions:

(a) What is the length of the hypotenuse?

(b) Consider the acute angle adjacent to the 12-length side. What is its sine? (You should not need a calculator for that.)

(c) What is its cosine?