Question

the measure of an angle is 20.9°. what is the measure of its supplementary angle?

Explanation:

Step1: Recall supplementary angle definition

Supplementary angles sum to \(180^\circ\). Let the supplementary angle be \(x\). So, \(20.9^\circ + x = 180^\circ\).

Step2: Solve for \(x\)

Subtract \(20.9^\circ\) from both sides: \(x = 180^\circ - 20.9^\circ\). Calculate \(180 - 20.9 = 159.1\). So, \(x = 159.1^\circ\).

Answer:

\(159.1^\circ\)