Final answer:
A proof by contrapositive is a method of proving a conditional statement by showing that its contrapositive statement is true.
Step-by-step explanation:
If we prove that p → q is true by showing that if p is true, q is never false, we are giving a proof by contrapositive. A proof by contrapositive is a method of proving a conditional statement by showing that its contrapositive statement is true. In this case, if we can show that if q is false, then p is false, we can conclude that p → q is true.