Determine the length of missing side by using pythagoras theorem.
[tex]\begin{gathered} (11)^2=(\frac{39}{10})^2+x^2 \\ x^2=121-\frac{1521}{100} \\ =\frac{12100-1521}{100} \\ =\frac{10579}{100} \\ x=\sqrt[]{\frac{10579}{100}} \\ =\frac{1}{10}\sqrt[]{10579} \\ =\frac{102.85}{10} \\ \approx10.3 \end{gathered}[/tex]So answer is,
[tex]\frac{1}{10}\sqrt[]{10579}[/tex]Or 10.3.