Two angles are supplementary if their measures add up to 180 degrees. Given that one angle measures 110°, we can set up the equation:
\[ x + 110° = 180° \]
To find \( x \), we can subtract 110° from both sides of the equation:
\[ x = 180° - 110° \] \[ x = 70° \]
Therefore, the measure of angle \( x \) is:
\[ x = 70° \]