Question

angles x and y are supplementary. angle x is 3 times the measure of angle y. what is the measure of angle x?
$45^\circ$
$60^\circ$
$120^\circ$
$135^\circ$

Explanation:

Step1: Define supplementary angles

Supplementary angles sum to $180^\circ$, so $X + Y = 180^\circ$.

Step2: Relate X and Y

Given $X = 3Y$, substitute into the equation: $3Y + Y = 180^\circ$.

Step3: Solve for Y

Combine terms: $4Y = 180^\circ$, so $Y = \frac{180^\circ}{4} = 45^\circ$.

Step4: Calculate X

Substitute Y back: $X = 3 \times 45^\circ = 135^\circ$.

Answer:

135° (Option D. 135°)