How do I find the length of one side if I only have one other side and the angle

Come on. Be more specific. A right triangle? Which side? Which angle?

Apply trignometery... draw perpendicular from the side u don't know and apply trignometeric ratios

I think you need the length of 2 sides and 1 angle, or 2 angles and the 1 length.

If it's a right angled triangle, you can do it using sine, cosine or tangent functions with the information you have. (but then, as start says, you really know 2 angles and a side, don't you).