What are two angles that add up to 180 that share a common vertex.?

Two angles that add up to 180 degrees and share a common vertex are called supplementary angles. For example, if one angle measures 70 degrees, the other angle must measure 110 degrees to satisfy the condition, since 70 + 110 = 180. These angles can be adjacent, forming a straight line, or they can be separate but still share the same vertex.