Angles X and Y are supplementary. Angle X measures 115.75° and angle Y measures (m − 8)°. Find m∠Y.
a 136.5°
b 128.5°
c 72.25°
d 64.25°
The sum of supplementary angles is 180°. Since angle X measures 115.75°, we can write the equation 115.75° + (m - 8)° = 180°.
Simplifying the equation, we get m - 8 + 115.75 = 180.
Combine like terms, we get m + 107.75 = 180.
Subtract 107.75 from both sides, we get m = 72.25.
Therefore, m∠Y = m - 8 = 72.25 - 8 = 64.25°.
The answer is d) 64.25°.