Answer:
supplementary angles
Explanation:
Two line are parallel lines
line with angles 1 and 2 is the traversal line that intersects two parallel lines
Alternate interior angles are equation in parallel lines
HEre angle 1 and angle 2 are adjacent angles
Adjacent angles are supplementary angles
Sum of adjacent angles is 180 degree
Supplementary angles are 180 degree
So angle 1 and 2 are supplementary angles