What is the significance of the circle of fifths in music theory and how does it help musicians understand key relationships and chord progressions?

The circle of fifths is a tool in Music Theory that shows the relationship between different keys and their corresponding chords. It helps musicians understand how keys are related to each other and how chord progressions can be created based on these relationships. By following the circle of fifths, musicians can easily determine which chords are likely to sound good together in a given key, making it easier to compose music and improvise.