Question

the measure of an angle is 71°. what is the measure of its supplementary angle?

Explanation:

Step1: Recall supplement - angle formula

The sum of an angle and its supplementary angle is 180°. Let the given angle be $\theta = 71^{\circ}$ and its supplementary angle be $\alpha$. Then $\theta+\alpha = 180^{\circ}$.

Step2: Solve for the supplementary angle

We can rewrite the formula as $\alpha=180^{\circ}-\theta$. Substitute $\theta = 71^{\circ}$ into the formula: $\alpha = 180^{\circ}-71^{\circ}$.
$180 - 71=109$. So $\alpha = 109^{\circ}$.

Answer:

$109^{\circ}$