How is Smaug finally defeated In the hobbit?

Smaug is finally defeated when Bard the Bowman, a skilled archer from Lake-town, learns of the dragon's weak spot—a missing scale on his underbelly. Using this knowledge, Bard shoots a precise arrow that strikes Smaug in the vulnerable area, killing him. The death of the dragon leads to the release of his hoarded treasure, which becomes a pivotal point in the story and sets off a series of conflicts over the riches.