A triad written with the third as the lowest note.

• A. Second Inversion
• B. First Inversion
• C. Root Position
• D. Third Inversion

Answer: (B)

When a triad has its lowest sounding note as the third of the triad, that arrangement is in the first inversion. In a triad, the three tones are the root, the third, and the fifth. If the bass note is the third, you’ve moved the triad so that the third sits in the bass, which is what we call the first inversion.

For example, take a C major triad: C–E–G. In root position, C is in the bass. If the lowest note is E (the third of C major) and the other notes fill in above, you’ve created the first inversion. If the bass were G (the fifth), that would be the second inversion, and if the bass returns to C, you’re back in root position.