Final answer:
On April 20, 1803, the Louisiana Purchase deal was made. Napoleon sold the territory to the U.S. due to the cost of the Haitian war and the upcoming conflict with Britain, and considering the strategic challenge of defending the vast territory.
Step-by-step explanation:
The deal made on April 20, 1803, was the Louisiana Purchase. Napoleon was willing to make this deal with the U.S. for two main reasons. Firstly, the expense of the failed war to prevent Haitian independence was a considerable burden, and Napoleon needed funds to prepare for a new war with Britain.
The Louisiana Purchase greatly benefited the U.S. by doubling the size of the country and securing control over the Mississippi River, which was crucial for trade and expansion into the interior of North America. The U.S. acquired the territory from France for $15 million, which amounted to roughly four cents an acre—a significant bargain for the United States.