with right-angled triangles there's: a^2 = b^2 + c^2 to find out the length of a side if the other two are known.
if an angle and a side are known then you have to label the triangle with hypotenuse (longest, slanted side), opposite (angle (not right angle)) and adjacent the to the angle. and then if you just sick with the S o/h, C a/h, T o/a. S being sin, C being cos and T being tan. then do eg., tan36(degrees) = x/10 so x = 10tan36. if you need to fin out an angle you'll have to use the tan-1 function.!
it doesn't take long at all if you know what you're doing :) do a few practice questions and it'll all come you!
also do you need to know the sine and cosine rule? :) x
What Kelly said, the SOH CAH TOA mnemonic should be sufficient to learn for the exam, for the cosine and the sine rule should be given to you on the first page of the exam, if you are taking the Edexcel exam like I am ;)