Chapter P - Preliminary Concepts - P.2 - Statement and Reasoning - Exercises P.2 - Page 14: 18

H: It is an isosceles triangle. C: Base angles are congruent.

We write this in "if-then" form to help us identify the hypothesis and the conclusion. We can write this statement as "if it is an isosceles triangle, then base angles are congruent." Thus, we see that the hypothesis is "it is an isosceles triangle," and the conclusion is "base angles are congruent."