Question

Angles A and B are supplementary. Angle A has a measure of 80°. What is the measure of angle B?

The measure of angle B is

Answer 1

Answer is 100. Supplementary basically means 2 angles ,when added form 180. If angle 1 is mentioned as 80. Angle 2 will be whole - angle 1
=180 - 80
=90 degrees

Just In case you are wondering what complementary means it’s the same thing but instead of the angles forming 180 it will form 90.

Hope you have understood

Answer 2

The measure of angle B would be 100°

Explanation:

Supplementary means two angles add up to 180 degrees. Let's say A+B=180. Since we know what A is, we can substitute that in, B+80=180. Now solve. B=100