Complementary angles are two angles whose measures add up to 90 degrees. Given one angle is 115°, you can find the measure of angle X by using the equation:
\[ x + 115° = 90° \]
To find \( x \), subtract 115° from both sides:
\[ x = 90° - 115° \] \[ x = -25° \]
Since angles cannot have negative measures in this context, it indicates that the given angles cannot be complementary. Therefore, there is no valid measure for angle \( x \) that satisfies the conditions provided in the problem.