Exercise 4 Page 246

Let's analyze each step in the given proof and verify whether it is true. The fist two statements tell us that $\overline{KH}$ and $\overline{NH}$ are congruent sides, and that $\angle L$ and $\angle M$ are congruent angles. Since this information is given, we know that these two statements are correct.

The next statement says that $\angle KHL$ is congruent to $\angle MHN$ because they are vertical angles. Analyzing the diagram, we can see that these angles are indeed vertical angles. Moreover, the Vertical Angles Theorem ensures us that they are congruent. We can conclude that this statement is also correct.