yes, angle 1 and angle 2 can be called a pair of supplementary angles ... supplementary angles do not need to be adjacent.
an adjacent pair of supplementary angles is called a linear pair of angles.
Please have a look at the image below where m & n are 2 parallel lines & t is a transversal. Now
angle 1 + angle 2 = 180 degrees
because interior angles on the same side of the transversal are supplementary but can (angle 1 + angle 2) be called supplementary angles?
Thanks,
Ron