To find x we need to use the tangent function, remember that this is defined as:
[tex]\tan \theta=\frac{\text{opp}}{\text{adj}}[/tex]
For the angle of 60° then we have:
[tex]\begin{gathered} \tan 60=\frac{20}{x} \\ x=\frac{20}{\tan 60} \end{gathered}[/tex]
Therefore the expression we can use is option C.
