3.2 Inversions & Figured Bass

Inversions

A triad is in root position when the root is lowest, first inversion when the third is lowest, and second inversion when the fifth is lowest.

Figured bass

Figured bass numbers show intervals above the bass. Root position = 5/3 (usually unmarked); first inversion = 6 (or 6/3); second inversion = 6/4.

Roman numeral figures

Combined with Roman numerals: V6 is a dominant triad in first inversion; I6/4 is a tonic in second inversion. The figures tell you which chord tone is in the bass.

Key terms

Root position

root in the bass (figured 5/3)

First inversion

third in the bass (figured 6)

Second inversion

fifth in the bass (figured 6/4)

Figured bass

numbers = intervals above the bass note

V6

dominant triad in first inversion

Try an AP-style question

A triad with the third in the bass is in…

1. second inversion
2. third inversion
3. first inversion
4. root position