Final answer:
The Iran hostage crisis ended on January 20, 1981, when the hostages were released on the day Ronald Reagan took office as the US President.
Step-by-step explanation:
The Iran hostage crisis ended on January 20, 1981, when the hostages were released on the day Ronald Reagan took office as the US President. The hostages had been held captive for 444 days following the storming of the US embassy in Tehran by Iranian students on November 4, 1979.
During their captivity, negotiations failed to secure their release, and a rescue attempt in April 1980 was unsuccessful. The hostage crisis had a significant impact on US-Iran relations and played a role in President Carter's loss in the 1980 elections.
It was eventually revealed that as part of a deal, the United States agreed to sell arms to Iran to secure the release of the American hostages. The release of the hostages on Reagan's inauguration day furthered the image that Carter was to blame for the lengthy crisis.