Final answer:
To find the measure of a supplementary angle, subtract the measure of the given angle from 180°. The measure of the supplementary angle to an angle of 161° is 19°.
Step-by-step explanation:
To find the measure of a supplementary angle, we need to subtract the measure of the given angle (161°) from 180°.
Supplementary angles are two angles that add up to 180°. So, by subtracting the measure of the given angle from 180°, we can find the measure of its supplementary angle.
Therefore, the measure of the supplementary angle to an angle of 161° is 19°.