Using the triangle sum theorem, which states The sum of interior angles in a triangle is always 180:
[tex]\begin{gathered} m\angle K+m\angle L+m\angle J=180 \\ 75+38+6x-11=180 \\ 102+6x=180 \\ \text{solve for x:} \\ 6x=78 \\ x=\frac{78}{6} \\ x=13 \end{gathered}[/tex]
