1) From the data, we can see that
is given.
2) Next,
since they are alternate angles.
3) By substitution, these means that
4) Finally, a || b since
this is because, angle 7 and angle 8 are corresponding angles.
Corresponding angles are angles that are on the same corner at each intersection. For instance, 2 and 6
4 and 8, 1 and 5, 3 and 7
In our case, 7 and 8 are corresponding angles