Question

the measure of an angle is 102.2°. what is the measure of its supplementary angle?

Explanation:

Step1: Recall supplementary - angle definition

Supplementary angles add up to 180°.

Step2: Calculate the supplementary angle

Let the given angle be $\alpha = 102.2^{\circ}$, and the supplementary angle be $\beta$. Then $\beta=180^{\circ}-\alpha$.
Substitute $\alpha = 102.2^{\circ}$ into the formula: $\beta = 180 - 102.2=77.8^{\circ}$.

Answer:

$77.8$