Angles X and Y are supplementary. Angle X measures 127.42°, and angle Y measures (m − 12)°. Find m∠Y.

a) 115.42°
b) 74.84°
c) 64.58°
d) 52.58°

Since angles X and Y are supplementary, we have:

X + Y = 180

Substituting the given values, we get:

127.42 + (m - 12) = 180

Simplifying the equation, we have:

m - 12 = 180 - 127.42
m - 12 = 52.58

Adding 12 to both sides of the equation, we get:

m = 64.58

Therefore, the measure of angle Y is:

m - 12 = 64.58 - 12 = 52.58°

The correct option is d) 52.58°.