The two angles of a linear pair are always supplementary , which means their measures add up to 180° .

Are all linear pairs supplementary?

Not all supplementary angle form a linear pair. But, all linear pairs are supplementary.

Are linear pairs supplementary or equal?

A linear pair forms a straight angle which contains 180º, so you have 2 angles whose measures add to 180, which means they are supplementary. If two congruent angles form a linear pair, the angles are right angles.