Final answer:
The purpose of the Judiciary Act of 1789 was to establish a federal judiciary system in the United States, creating lower federal courts and fixing the size of the Supreme Court.
Step-by-step explanation:
The purpose of the Judiciary Act of 1789 was to establish a federal judiciary system in the United States. Under the Articles of Confederation, there was no national judiciary, leading to inconsistent interpretation of national laws by individual states. The Judiciary Act of 1789 remedied this problem by creating lower federal courts and fixing the size of the Supreme Court. It also defined the jurisdiction and powers of the federal courts, ensuring a uniform interpretation of the law across the country.