Chapter P - Preliminary Concepts - P.2 - Statement and Reasoning - Exercises P.2 - Page 14: 16

H: Two lines intersect C: Vertical angles are congruent

The hypothesis typically follows the word IF or the word WHEN, though this is not always the case. The hypothesis is the hypothetical statement that may or may not happen. The conclusion is what will happen if the hypothesis is true. In this case, we see that the hypothesis is "Two lines intersect," and the conclusion is "Vertical angles are congruent."