Although the angle measurement of straight is equal to 180 degrees, a straight angle can't be called a supplementary angle because the angle only appears in a single form. For angles to be called supplementary, they must add up to 180° and appear in pairs.

What angles are supplementary?

Supplementary angles are two angles with a sum of 18 0 ∘ 180 ^\circ 180∘ . A common case is when they lie on the same side of a straight line.

What angles Cannot be supplementary?

We know, two angles are Supplementary when they add up to 180 degrees. We get 182∘, which is greater than 180∘. Hence, two obtuse angles i.e., angle which is greater than 90 degrees, can never be supplementary as their sum is not coming equal to 180∘ and to be supplementary the angles sum should be equal to 180∘.