By definition:
[tex]\tan (angle)=\frac{\text{opposite}}{\text{adjacent}}[/tex]
Applying this definition to the triangle in the picture:
[tex]\tan (42^o)=\frac{x}{35}[/tex]
Solving for x:
[tex]\begin{gathered} \tan (42^o)\cdot35=x \\ 31.51=x \end{gathered}[/tex]
