What is the interval designation for a 3rd inversion seventh chord?

For a 3rd inversion seventh chord, the interval designation reflects the lowest note, which is the seventh of the chord. In this case, the bass note is the seventh degree of the chord structure, resulting in an interval designation of 4/2.

In a seventh chord, the numbers indicate the intervals above the bass note. Here, "4" signifies that there is a fifth (which is the root) above the bass, and "2" indicates that there are two notes (the third and fifth) above that bass note. This is why a 3rd inversion seventh chord is denoted as 4/2, as the intervals set up this configuration with the seventh being the lowest note.

Understanding this designation helps musicians and composers work within figured bass and recognize harmonic structures quickly, ensuring they are capable of accurately interpreting and performing the music as intended.