Recall that the Angle-Angle criterion states that two triangles are similar if two of their angles are congruent.
Now, recall that the interior angles of a triangle add up to 180 degrees, therefore, the other side of the largest triangle has measure
[tex]180^{\circ}-115^{\circ}-38^{\circ}=27^{\circ}.[/tex]Therefore, the values that x could be are:
[tex]27\text{ or 115.}[/tex]Answer: First option.
[tex]27\text{ or 115.}[/tex]