How to find a missing side of a right triangle using one side and one angle calculator?

This is one of my favorite things to do! You need to remember SOH CAH TOA
which describes the relationship of right triangle sides and angles. 
S stands for Sine -opposite over hypotenuse (the side opposite of an angle)
C stands for cosine - adjacent over hypotenuse (the side next to the angle)
T stands for tangent - opposite over adjacent  The hypotenuse is always across from the right triangle.
TO solve for a missing side, look at the sides you're given in relation to the angle given.  Say your ladder is leaning up against a building. you know the ladder is 10 ft long. You happen to know that the angle of said ladder against the building is 20 degrees. You want to know how far up the building the ladder will reach, So you have the hypotenuse (draw a pic if it helps I always do) and you have the angle  Set up an equation based on what you have and what you need to find. You're looking for the opposite of your angle so you have SOH  sin=opp/hypotenuse.  Plug in what you know sin(20)=x/10 its just an equation multiply both sides by 10 to get x alone. YOu should have a sin key on your calculator. You'll plug in 10sin(20) and hit enter. If you get a negative or a decimal check your mode and make sure its in degrees. If you are given the angle measure in radians then make sure you are set to radians.