Question

Find the measure of an angle that is 20° less than its supplement.

Answer 1

Let the measure of the angle be x$°$.
Then, the measure of its supplement will be (180 - x)$°$.
$$\begin{gathered} \Rightarrow \left(180-x\right)-x=20 \\ \Rightarrow 180-2x=20 \\ \Rightarrow 160=2x \\ \Rightarrow x=80 \end{gathered}$$
Therefore, the measure of the required angle is ${80}^{\circ }$.