Final answer:
The event in U.S. history that is synonymous with William Randolph Hearst and Yellow Journalism is the Spanish-American War. Hearst and Joseph Pulitzer used yellow journalism to agitate for war.
Step-by-step explanation:
The event in U.S. history that is synonymous with William Randolph Hearst and Yellow Journalism is the Spanish-American War. Hearst, along with newspaper publisher Joseph Pulitzer, used yellow journalism to agitate for war with Spain. Yellow journalism is a technique of using sensationalized headlines and little to no factual reporting to stir up public emotion. In the case of the Spanish-American War, the newspapers exaggerated and distorted the situation in Cuba to generate support for military intervention.