Final answer:
To join claims for supplemental jurisdiction in federal court, the claims must be related to the same case or controversy as the original claim that gave the court jurisdiction.
Step-by-step explanation:
In order to join claims for supplemental jurisdiction in federal court, the factual requirement that must be met is that the claims must be related to the same case or controversy as the original claim that gave the court jurisdiction. This means that the claims must arise out of the same set of facts or events. For example, if a federal court has jurisdiction over a claim involving a federal question, it may also hear related state law claims that are part of the same case.