Not quite. $\displaystyle Cos(82)=\frac{x}{23}$
Remember 'Sohcahtoa' - $\displaystyle Sin = \frac{Opp}{Hyp}; Cos = \frac{Adj}{Hyp}; Tan = \frac{Opp}{Adj}$
Where 'adj' = the line adjacent to the angle, 'opp' = the line opposite the angle, and 'hyp' is the hypotenuse - the longest side.
I'm sure you can solve from there.
Edit:I assumed you meant that you wanted to find X. If it's the missing angle you need, then see below.