We can relate an angle and a side length in a right triangle using trigonometric ratios.
In this case, we can calculate x as:
[tex]\begin{gathered} \sin (35\degree)=\frac{\text{Opposite}}{\text{Hypotenuse}}=\frac{x}{20} \\ x=20\cdot\sin (35\degree) \\ x\approx20\cdot0.574 \\ x\approx11.5 \end{gathered}[/tex]
Answer: x = 11.5
