Question

the measure of an angle is 39.1°. what is the measure of its supplementary angle?

Explanation:

Step1: Recall the definition of supplementary angles

Supplementary angles add up to 180°.

Step2: Set up the equation

Let the measure of the supplementary angle be $x$. Then $x + 39.1^{\circ}=180^{\circ}$.

Step3: Solve for $x$

$x=180^{\circ}- 39.1^{\circ}=140.9^{\circ}$

Answer:

$140.9^{\circ}$