Why was the united states involved in the korean war ?

 On June 25, 1950, the Korean War began when North Korea, supported by the Soviet Union and China, invaded South Korea, which was supported by the United States. General MacArthur, leader of the United Nations forces, drove the North Koreans back across the divide, yet encountered a Chinese invasion.

I'm going to go with 1,982 feet because of all of the ice.                                               ps its this is not the answer go with d 6,500.