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AP Music Theory Unit 3, Music Fundamentals III: Triads and Seventh Chords, covers 5 topics on triads and seventh chords, the core building units of harmony in tonal music, including how they're constructed, identified, and labeled with Roman numerals. You'll work through the four chord qualities (major, minor, diminished, augmented), diatonic chords, and chord inversions with figured bass notation. AP Music Theory then pushes into seventh chords and their inversions, where that stacked-thirds logic gets a fourth note and a noticeably richer, more complex sound.
AP Music Theory Unit 3 covers triads and seventh chords, the basic building blocks of harmony in tonal music. You learn how chords are stacked in thirds, how their quality (major, minor, diminished, augmented) gives each one a distinct sound, and how to label them with Roman numerals and figured bass symbols. The single biggest idea is that every chord in a key can be named precisely by three pieces of information: which scale degree it's built on, what quality it is, and which chord member sits in the bass.
| Chord | Construction | Sound and tendency | Figured bass (all positions) |
|---|---|---|---|
| Major triad | M3 + P5 above root | Bright, stable | 5/3, 6, 6/4 |
| Minor triad | m3 + P5 above root | Darker, stable | 5/3, 6, 6/4 |
| Diminished triad | m3 + d5 above root | Tense, wants to resolve | 5/3, 6, 6/4 |
| Augmented triad | M3 + A5 above root | Bright but unstable | 5/3, 6, 6/4 |
| Major seventh (M7) | Major triad + M7 | Lush, restful | 7, 6/5, 4/3, 4/2 |
| Dominant seventh (Mm7) | Major triad + m7 | Strong pull toward tonic | 7, 6/5, 4/3, 4/2 |
| Minor seventh (m7) | Minor triad + m7 | Mellow, often ii or vi | 7, 6/5, 4/3, 4/2 |
| Half-diminished (ø7) | Diminished triad + m7 | Tense, often vii in major | 7, 6/5, 4/3, 4/2 |
| Fully-diminished (°7) | Diminished triad + d7 | Maximum tension, often vii in minor | 7, 6/5, 4/3, 4/2 |
Units 1 and 2 give you pitches, scales, and keys. Unit 3 is where those raw materials become harmony, and harmony is what the back half of the course is about. Roman numerals and figured bass are the analytical language for everything from cadences to secondary dominants, so fluency here decides how comfortable the rest of the year feels.
This unit's content runs through both halves of the AP Music Theory exam. On the multiple-choice section, you identify chord qualities and inversions in notated scores, and aural questions play a chord or short progression and ask you to name its quality or position. Score-based question sets often ask you to supply the Roman numeral with the correct figure for a chord in context, which means spelling the chord, checking the key, and finding the bass note all at once.
On the free-response section, this unit is the foundation of the figured bass realization question, where you read figures under a bass line and write the implied chords in four voices, and the Roman numeral analysis embedded in the harmonization questions. Sight-singing and melodic dictation also get easier when you recognize arpeggiated triads and seventh chords inside a melody instead of reading note by note. The reliable move on any harmony question is the same three-step check: find the root, determine the quality, identify the bass note.
AP Music Theory Unit 3 covers 5 topics built around roman numerals and chord construction: Triad and Chord Qualities (M, m, d, A), Diatonic Chords and Roman Numerals, Chord Inversions and Figured Bass, Seventh Chords, and Seventh Chord Inversions and Figures. Together they form the harmonic foundation you'll use throughout the course. Here's the full topic list: - 3.1 Triad and Chord Qualities - 3.2 Diatonic Chords and Roman Numerals - 3.3 Chord Inversions and Figures: Introduction to Figured Bass - 3.4 Seventh Chords - 3.5 Seventh Chord Inversions and Figures See everything in one place at AP Music Theory Unit 3.
The AP Music Theory Unit 3 progress check pulls MCQ and FRQ questions directly from all five unit topics, with a heavy focus on roman numerals, triad qualities, chord inversions, and seventh chord identification. MCQ questions typically ask you to identify chord quality or figured bass symbols. FRQ tasks may ask you to notate or analyze chords in context. The MCQ portion tests recognition skills: spotting major, minor, diminished, and augmented triads, reading inversion figures, and labeling diatonic chords with roman numerals. The FRQ portion pushes you to apply those same skills in writing, often combining topics from 3.2 through 3.5. Practice with questions matched to every progress check topic at AP Music Theory Unit 3.
AP Music Theory Unit 3 FRQs most often come from the chord notation and analysis topics: roman numerals (3.2), chord inversions and figured bass (3.3), and seventh chord inversions (3.5). Typical question types ask you to write a chord in a given inversion, supply the correct figured bass symbol, or label a progression with roman numerals. To practice effectively, work through each topic in order. Start by drilling triad qualities until you can write all four (M, m, d, A) from memory. Then move to figured bass figures for inversions, since those symbols show up constantly in FRQ prompts. Finally, repeat the same process for seventh chords and their inversions. Timed, written repetition is the key. Write out full chord stacks on staff paper rather than just identifying them mentally. Find topic-matched FRQ practice at AP Music Theory Unit 3.
The best place to find AP Music Theory Unit 3 practice questions, including multiple-choice and practice test sets, is the AP Music Theory Unit 3 page, where questions are organized by topic. You'll find MCQ drills covering triad qualities, roman numerals, chord inversions, and seventh chords, all aligned to what College Board actually tests. For a practice-test experience, work through the MCQ sets topic by topic (3.1 through 3.5), then attempt the FRQ-style notation tasks under timed conditions. Mixing both formats gives you the same variety you'll see on the real exam.
Start AP Music Theory Unit 3 by locking in roman numerals and triad qualities before moving to anything else, since every later topic builds on them. A clear study sequence makes this unit manageable across a week or two. **Step-by-step plan:** 1. **3.1 Triad Qualities.** Memorize the interval stacks for major, minor, diminished, and augmented triads. Write them in every key. 2. **3.2 Diatonic Chords and Roman Numerals.** Practice labeling all seven diatonic chords in major and minor keys with roman numerals. Flashcards help here. 3. **3.3 Chord Inversions and Figured Bass.** Learn the figures (root position, 6, 6/4) and practice identifying inversions by ear and on the staff. 4. **3.4 Seventh Chords.** Add the seventh on top of each triad quality and learn the five seventh chord types. 5. **3.5 Seventh Chord Inversions.** Apply the same inversion logic from 3.3, now with four possible positions per chord. Spend the most time on topics 3.2 and 3.3 since chord inversions and roman numeral analysis appear on nearly every AP Music Theory FRQ. Review everything at AP Music Theory Unit 3.