Final answer:
President Polk confirmed the discovery of gold in California via a written statement.
Step-by-step explanation:
In January 1848, James Marshall discovered gold in the millrace of the sawmill he had built with his partner John Sutter on the American River in California. Word quickly spread, and within a few weeks, people from all over California, and eventually from around the world, flocked to the gold fields in search of riches. This event is known as the California Gold Rush.
President James K. Polk confirmed the gold discovery in California through a written statement, rather than a personal announcement or a speech at the White House. The news of the gold discovery likely reached President Polk through various reports, and he chose to confirm it in writing. This written confirmation played a significant role in attracting thousands of people to California in search of gold.