Answer:
The corresponding angles theorem works for cases where we have two parallel lines intersecting another line.
Two lines are parallel if, at any point, the distance between these two lines is always the same.
Now, if we look at the image, we can see that the distance between the two horizontal lines changes (is smaller at the right and larger at the left)
Thus, these lines are not parallel.
Then the corresponding angles theorem can not be used here, and we have that:
∠9 ≠ ∠10
