Triad and Chord Qualities (M, m, d, A)
Build and identify the four triad qualities by stacking thirds and measuring intervals from the root. Recognize each quality aurally and in notation.
AP Music Theory Unit 3 Review: Triads and Seventh Chords
- 5 topics
- AP exam review verified for 2027
A triad stacks two thirds to produce a root, third, and fifth. A seventh chord adds one more third on top. The quality of each chord depends on the specific sizes of those intervals. Roman numerals name the chord by scale degree and quality, and figured bass figures specify which chord member is in the bass.
Fiveable's AP Music Theory Unit 3 review covers 5 topics, with guided practice questions for the unit.
AP Music Theory unit 3 topics
Diatonic Chords and Roman Numerals
Label every diatonic triad and seventh chord in major and minor keys using Roman numerals that encode scale degree, quality, and key context.
Chord Inversions and Figures: Introduction to Figured Bass
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.
Seventh Chords
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.
Seventh Chord Inversions and Figures
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.
Practice AP Music Theory unit 3 questions
Try AP-style questions on unit 3, then use the review notes below for anything you miss.
Unit 3 review notes
3.1
Triad Qualities: Major, Minor, Diminished, Augmented
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).
- Major triad (M): Major third (4 semitones) plus minor third (3 semitones); root to fifth is a perfect fifth (7 semitones). Bright, stable sound.
- Minor triad (m): Minor third (3 semitones) plus major third (4 semitones); root to fifth is a perfect fifth. Darker, softer sound than major.
- Diminished triad (d or °): Two minor thirds stacked; root to fifth is a diminished fifth (6 semitones, a tritone). Tense, unstable sound.
- Augmented triad (A or +): Two major thirds stacked; root to fifth is an augmented fifth (8 semitones). Ambiguous, unsettled sound.
- Arpeggiation: Successive sounding of chord tones rather than simultaneous; the chord is still analyzed as a unit.
Spell a D diminished triad and an F augmented triad from scratch, then check your interval sizes from the root.
| 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 |
3.2
Diatonic Chords and Roman Numeral Analysis
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.
- Diatonic triads in major: I (M), ii (m), iii (m), IV (M), V (M), vi (m), vii° (d). Memorize this pattern.
- Diatonic triads in natural minor: i (m), ii° (d), III (M), iv (m), v (m), VI (M), VII (M). Note the lowercase v and the absence of a leading tone.
- Roman numeral case: Uppercase Roman numerals indicate major quality; lowercase indicate minor. The symbols ° and + are added for diminished and augmented.
- Scale-degree names: Tonic (1), supertonic (2), mediant (3), subdominant (4), dominant (5), submediant (6), leading tone (7 in major).
- Seventh chord Roman numerals: A 7 is appended to the Roman numeral: I7, ii7, V7, vii°7. Quality of the seventh is implied by the Roman numeral and key context.
Write out all seven diatonic triads in G major and in A natural minor using Roman numerals, then check each quality.
| 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) |
3.3
Chord Inversions and Figured Bass
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.
- Root position (5/3): Root is in the bass. The figure 5/3 is usually omitted; the Roman numeral alone implies root position.
- First inversion (6): Third of the chord is in the bass. Labeled with 6 appended to the Roman numeral: I6, IV6, V6.
- Second inversion (6/4): Fifth of the chord is in the bass. Labeled 6/4: I6/4, V6/4. The 6/4 chord is often unstable and requires resolution.
- Figured bass accidentals: A slash through a figure or a plus sign raises that interval by a half step. A lone accidental below the bass inflects the pitch a third above.
- Slash chord notation: Lead-sheet shorthand: C/E means a C major triad with E in the bass, equivalent to I6 in C major.
Given a bass note of G with the figure 6, identify the chord and its inversion in C major.
| 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 |
3.4
Seventh Chord Qualities
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.
- Major seventh (MM / M7): Major triad plus major seventh. Warm, stable but slightly open sound. Built on I and IV in major.
- Dominant seventh (Mm7 / major-minor): Major triad plus minor seventh. The most common seventh chord; built on V. Contains a tritone between its third and seventh that drives resolution to tonic.
- Minor seventh (mm / m7): Minor triad plus minor seventh. Softer dissonance. Built on ii, iii, and vi in major.
- Half-diminished seventh (ø7 / diminished-minor): Diminished triad plus minor seventh. Built on vii in major and ii in minor. Less tense than fully diminished.
- Fully diminished seventh (°7 / diminished-diminished): Diminished triad plus diminished seventh. Symmetrical, highly tense. Built on vii in minor (with raised 7th scale degree).
Name the quality of the seventh chord built on scale degree 2 in C major, then on scale degree 7 in A minor.
| 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 |
3.5
Seventh Chord Inversions and Figured Bass
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.
- Root position (7): Root in the bass. Figure: 7. Example: V7.
- First inversion (6/5): Third in the bass. Figure: 6/5. Example: V6/5.
- Second inversion (4/3): Fifth in the bass. Figure: 4/3. Example: V4/3.
- Third inversion (4/2 or 2): Seventh in the bass. Figure: 4/2, often abbreviated as 2. Example: V4/2. Unique to seventh chords.
- Resolution of the chordal seventh: The seventh of any seventh chord tends to resolve downward by step in the voice that holds it, regardless of inversion.
Label the inversion of a G dominant seventh chord with F in the bass, then write the complete Roman numeral with figure in C major.
| 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 |
Key terms
| 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. |
How to review unit 3
Topics students miss most
Miss rates come from Fiveable multiple-choice practice.
Common unit 3 mistakes
Confusing chord quality with key quality
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.
Mixing up half-diminished and fully diminished seventh chords
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).
Forgetting that third inversion only exists for seventh chords
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.
Writing the Roman numeral without the figure
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.
Misreading figured bass accidentals
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.
How this unit shows up on the AP exam
Chord identification in notation and by ear
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.
Roman numeral analysis with figures
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.
Figured bass realization
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.
More ways to review
Topic study guides
Open the individual guides for Unit 3 when you want a closer review of one topic.
Practice questions
Use AP-style practice after you review the notes so you can check what you understand.
FRQ practice
Practice free-response reasoning and compare your answer with scoring guidance.
Cram archive videos
Watch past review streams filtered to Unit 3 when you want a video walkthrough.
Official unit cheatsheet
Open the Fiveable one-page unit review, then explore visual cheatsheets for a quick refresher.
Score calculator
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Unit 3 printables
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get printablesFrequently Asked Questions
What's on the AP Music Theory Unit 3 progress check (MCQ and FRQ)?
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.
How do I practice AP Music Theory Unit 3 FRQs?
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.
Where can I find AP Music Theory Unit 3 practice questions?
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.
How should I study AP Music Theory Unit 3?
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.