Angles X and Y are supplementary. Angle X is 3 times the measure of angle Y. What is the measure of angle X? 45°
60°
120°
135

∠ Y = 45°, ∠ X = 135°

Step-by-step explanation:

Since the 2 angles are supplementary, then

X + Y = 180 ← substitute X = 3Y

3Y + Y = 180, that is

4Y = 180 ( divide both sides by 4 )

Y = 45

and

X + Y = 180, so

X + 45 = 180 ( subtract 45 from both sides )

X = 135

Thus

∠ X = 135° and ∠ Y = 45°