Use the relationship between supplementary angles to determine the value of y° if x°=125° .
If two angles are supplementary, their sum is 180 degrees. Therefore, if x° = 125°, we can set up the equation:
x° + y° = 180°
Substituting x° = 125°:
125° + y° = 180°
Solving for y°:
y° = 180° - 125°
y° = 55°
Therefore, y° = 55°.