To find x we can use the trigonometric identity of sin so we know that
[tex]\sin (\theta)=\frac{oposite}{adyacent}[/tex]So in our triangle will be:
[tex]\sin (30)=\frac{10}{x}[/tex]and we solve for x
[tex]\begin{gathered} \frac{1}{2}=\frac{10}{x} \\ x=10\cdot2 \\ x=20 \end{gathered}[/tex]