Question

the measure of an angle is 153°. what is the measure of its supplementary angle?

Explanation:

Step1: Recall the definition of supplementary angles

Supplementary angles add up to 180°. Let the given angle be $\theta = 153^{\circ}$, and its supplementary - angle be $\alpha$. Then $\theta+\alpha = 180^{\circ}$.

Step2: Solve for the supplementary angle

We can find $\alpha$ by subtracting the given angle from 180°. So, $\alpha=180^{\circ}-\theta$. Substitute $\theta = 153^{\circ}$ into the formula: $\alpha = 180^{\circ}-153^{\circ}=27^{\circ}$.

Answer:

$27^{\circ}$