Answer:
The ralationship describes ∠ 1 and ∠2 are supplementary angles .
Explanation:
As the figure given in the question .
Definition of supplementary angles
Supplementary angles are two angles whose sum is 180 degrees .
Now as shown in the figure the sum of ∠1 and ∠2 is 180° .
Thus
∠ 1 + ∠ 2 = 180°
Therefore the ∠ 1 and ∠2 are supplementary angles .