Explanation:
corresponding angles : angles formed at the same relative position at each intersection, when a line crosses 2 (or more) other lines.
in this case, as the crossed lines are parallel, it means that the corresponding angles are equally sized.
in our example here, we have multiple pairs of corresponding angles :
1 and 5
2 and 6
3 and 7
4 and 8
so, angle 5 corresponds to angle 1.