Review AP Music Theory Unit 3 to build your foundation in triads and seventh chords, the core building blocks of tonal harmony. This unit covers chord quality, Roman numeral analysis, figured bass, and inversions for both triads and seventh chords.
Use the topic guides, key terms, and practice questions available for this unit to work through chord spelling, quality identification, and figured bass notation.
Unit 3 is where pitch knowledge from Units 1 and 2 becomes harmonic knowledge. You move from individual intervals and scales to chords: how they are built, what they sound like, how they are labeled, and how their bass note changes their notation.
Major (M): major third plus minor third, perfect fifth. Minor (m): minor third plus major third, perfect fifth. Diminished (d or °): two minor thirds, diminished fifth. Augmented (A or +): two major thirds, augmented fifth. Quality is determined by stacking the chord in thirds and measuring the intervals from the root.
Every scale degree in a key produces a diatonic chord. Uppercase Roman numerals label major triads, lowercase label minor, lowercase with ° labels diminished, and uppercase with + labels augmented. In C major: I, ii, iii, IV, V, vi, vii°. In natural minor: i, ii°, III, iv, v, VI, VII.
Root position places the root in the bass (5/3, abbreviated). First inversion places the third in the bass (6). Second inversion places the fifth in the bass (6/4). Seventh chords add a third inversion (4/2) where the seventh is in the bass. Figures attach to Roman numerals: V6, V6/5, V4/3, V4/2.
Every harmonic analysis task in AP Music Theory requires you to name a chord's quality and inversion simultaneously. A C major triad in first inversion is not just 'C major'; it is I6 in C major. Getting both the Roman numeral and the figure correct is the standard for full credit on any notation or analysis task in this course.
Build and identify the four triad qualities by stacking thirds and measuring intervals from the root. Recognize each quality aurally and in notation.
Label every diatonic triad and seventh chord in major and minor keys using Roman numerals that encode scale degree, quality, and key context.
Identify root position, first inversion, and second inversion for triads using figured bass numbers (5/3, 6, 6/4) and attach figures to Roman numerals.
Recognize and spell the five seventh chord qualities (M7, Mm7, m7, ø7, °7) and understand the chordal seventh as a dissonance that tends to resolve downward.
Apply figured bass shorthand (7, 6/5, 4/3, 4/2) to all four positions of a seventh chord and identify inversions in both notated and performed music.
This snapshot uses Fiveable practice activity to show where students tend to miss questions and which review moves are worth prioritizing first.
Across 223 multiple-choice practice attempts for this unit.
Practice activity included in this snapshot.
Review Chord Inversions and Figures: Introduction to Figured Bass with attention to how the concept appears in AP-style source and evidence questions.
Review Diatonic Chords and Roman Numerals with attention to how the concept appears in AP-style source and evidence questions.
A triad is built by stacking two thirds above a root, producing three chord members: root, third, and fifth. The four qualities differ in the sizes of those thirds and the resulting fifth. You need to identify quality both from notation (by measuring intervals) and by ear (by recognizing the characteristic sound of each quality).
| Quality | Lower third | Upper third | Root to fifth |
|---|---|---|---|
| Major (M) | Major (4 st) | Minor (3 st) | Perfect 5th |
| Minor (m) | Minor (3 st) | Major (4 st) | Perfect 5th |
| Diminished (°) | Minor (3 st) | Minor (3 st) | Diminished 5th |
| Augmented (+) | Major (4 st) | Major (4 st) | Augmented 5th |
Diatonic chords are built on each scale degree using only the pitches of the key. Roman numerals label both the scale degree of the root and the chord quality. Uppercase = major, lowercase = minor, lowercase + ° = diminished, uppercase + + = augmented. Scale-degree names (tonic, supertonic, mediant, subdominant, dominant, submediant, leading tone) are an alternate labeling system for the same chords.
| Scale degree | Major key quality | Natural minor quality |
|---|---|---|
| 1 (Tonic) | I (major) | i (minor) |
| 2 (Supertonic) | ii (minor) | ii° (diminished) |
| 4 (Subdominant) | IV (major) | iv (minor) |
| 5 (Dominant) | V (major) | v (minor) |
| 7 (Leading tone/subtonic) | vii° (diminished) | VII (major) |
Inversion is determined by which chord member sits in the bass. Figured bass uses Arabic numerals to show the intervals above the bass note, allowing you to identify both the chord and its inversion from a bass line alone. These figures attach to Roman numerals in analysis (e.g., I6, V6/4). You also need to read slash notation (C/E means C major with E in the bass) and recognize when a figure with a slash or plus sign raises a pitch by a half step.
| Inversion | Bass note | Figure | Roman numeral example |
|---|---|---|---|
| Root position | Root | (5/3) omitted | I |
| First inversion | Third | 6 | I6 |
| Second inversion | Fifth | 6/4 | I6/4 |
A seventh chord adds a fourth pitch (a third above the fifth) to a triad. The five qualities you need to know are defined by the combination of triad quality and the size of the added seventh. The chordal seventh is a chordal dissonance: it has a natural tendency to resolve, typically by moving down by step.
| Quality | Triad | Seventh interval | Common Roman numeral |
|---|---|---|---|
| Major seventh (M7) | Major | Major 7th | IM7, IVM7 |
| Dominant seventh (Mm7) | Major | Minor 7th | V7 |
| Minor seventh (m7) | Minor | Minor 7th | ii7, vi7 |
| Half-diminished (ø7) | Diminished | Minor 7th | viiø7 |
| Fully diminished (°7) | Diminished | Diminished 7th | vii°7 |
Because seventh chords have four notes, they can appear in root position or in three inversions. Each inversion is labeled with a specific figured bass shorthand attached to the Roman numeral. Third inversion is unique to seventh chords: the chordal seventh itself sits in the bass. Identifying inversions in both notation and by ear is a required skill.
| Inversion | Bass note | Figure | V7 example in C major |
|---|---|---|---|
| Root position | Root (G) | 7 | V7 |
| First inversion | Third (B) | 6/5 | V6/5 |
| Second inversion | Fifth (D) | 4/3 | V4/3 |
| Third inversion | Seventh (F) | 4/2 | V4/2 |
Try AP-style multiple-choice questions and written prompts after you review the notes.
| Term | Definition |
|---|---|
| root | The bottom note on which a chord is built when its pitches are arranged in stacked thirds. All chord members (third, fifth, seventh) are measured from the root. |
| Augmented triad | A triad built from two stacked major thirds, producing an augmented fifth between root and top note. Labeled with + in Roman numeral analysis. |
| Diminished triad | A triad built from two stacked minor thirds, producing a diminished fifth (tritone) between root and top note. Labeled with ° in Roman numeral analysis. |
| Roman numeral analysis | A system that labels chords by scale degree and quality: uppercase for major, lowercase for minor, with ° for diminished and + for augmented. Figures are appended to indicate inversion. |
| Supertonic | The second scale degree and the root of the ii (or ii°) chord. In major keys the supertonic triad is minor; in natural minor it is diminished. |
| Root Position | A chord voicing in which the root is the lowest note. For triads the figure 5/3 applies but is usually omitted; the Roman numeral alone implies root position. |
| Second Inversion Triad | A triad with the fifth in the bass, labeled with the figure 6/4 appended to the Roman numeral (e.g., I6/4). Often unstable and requires resolution. |
| Arabic numerals | The numbers used in figured bass to indicate intervals above the bass note, specifying chord inversion. Examples: 6 for first inversion triads, 6/5 for first inversion seventh chords. |
| Dominant Seventh Chord | A major-minor seventh chord (Mm7) built on scale degree 5. Contains a tritone between its third and seventh that creates strong tension resolving to the tonic. |
| Half-diminished seventh chord | A seventh chord with a diminished triad and a minor seventh (ø7). Built on vii in major and ii in minor; less tense than the fully diminished seventh. |
| Diminished seventh chord | A seventh chord with a diminished triad and a diminished seventh (°7). Symmetrical and highly dissonant; built on the raised leading tone in minor. |
| Minor seventh chord | A seventh chord with a minor triad and a minor seventh (m7). Found on ii, iii, and vi in major keys; softer dissonance than the dominant seventh. |
| Third Inversion | A seventh chord position in which the chordal seventh is in the bass. Labeled with the figure 4/2 (or abbreviated 2) appended to the Roman numeral. Exclusive to seventh chords. |
| inverted triad | A triad in which a chord member other than the root is in the bass. First inversion (third in bass, figure 6) and second inversion (fifth in bass, figure 6/4) are the two options. |
A minor key does not mean every chord is minor. In natural minor, scale degrees 3, 6, and 7 produce major triads (III, VI, VII). Always build the chord from the scale, not from the key name alone.
Both have a diminished triad on the bottom, but ø7 adds a minor seventh while °7 adds a diminished seventh. Check the interval from root to seventh: minor seventh (10 semitones) vs. diminished seventh (9 semitones).
Triads have only root position, first inversion, and second inversion. Third inversion (4/2) requires a fourth chord member, the seventh, to sit in the bass. Do not apply 4/2 to a triad.
A Roman numeral alone implies root position. If the chord is inverted, the figure must be written. V and V6 are different chords in analysis; omitting the 6 is an error.
A slash through a figure or a plus sign raises that specific interval by a half step, not the bass note. A lone accidental (no numeral) inflects the pitch a third above the bass, not the bass itself.
AP Music Theory tasks regularly ask you to identify a chord's quality and inversion from a notated score or from a recorded excerpt. For triads, you name the quality (M, m, d, A) and inversion. For seventh chords, you also specify the seventh chord quality (M7, Mm7, m7, ø7, °7). Both skills require you to stack the chord in thirds mentally and check interval sizes.
Harmonic analysis tasks require a complete Roman numeral label: the numeral itself (encoding scale degree and quality) plus the correct figured bass figure (encoding inversion). Writing V when the answer is V6/5 is incomplete. Practice writing full labels such as ii6, IV6/4, and vii°4/2 until the notation is automatic.
Given a bass line with figures, you may be asked to identify the implied harmonies and write Roman numerals, or to realize the figures by adding upper voices. Reading accidentals in figures (slashes, plus signs, and lone accidentals) is essential for correctly inflecting pitches above the bass, particularly in minor keys where the leading tone must be raised.
Open the individual guides for Unit 3 when you want a closer review of one topic.
browse guidesPractice free-response reasoning and compare your answer with scoring guidance.
practice FRQsWatch past review streams filtered to Unit 3 when you want a video walkthrough.
open videosUse unit cheatsheets for a quick visual review after you work through the notes.
open cheatsheetsEstimate your broader AP score goal after you review the course and exam format.
open calculatorAP 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.