How do Roman numerals label a chord's scale degree and quality, and how do we lay chords out in four voices?
Topic 3.5 Roman Numerals and SATB: label diatonic chords with Roman numerals showing root and quality, and arrange chord tones in the SATB four-voice texture.
A focused answer to AP Music Theory Topic 3.5, covering Roman numeral analysis (case shows quality, figures show inversion), the diatonic numerals of major and minor keys, the SATB four-voice layout and ranges, and how to spell a chord across four voices, with a worked analysis.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this topic is asking
The College Board (Topic 3.5) wants you to label diatonic chords with Roman numerals that show the chord's root scale degree and quality, add figures for inversion, and arrange the chord tones in the standard SATB (soprano, alto, tenor, bass) four-voice texture used for part-writing.
Roman numerals: root and quality
In a major key the diatonic triads are I, ii, iii, IV, V, vi and vii (diminished). In natural minor they are i, ii (diminished), III, iv, v, VI and VII; in harmonic minor the dominant becomes major (V) and the leading-tone chord becomes vii (diminished) because of the raised seventh degree. The numeral therefore carries two pieces of information at once: where the chord sits in the key and what it sounds like.
SATB four-voice texture
Because a triad has only three tones but there are four voices, one tone is doubled. The safest note to double is usually the root (or another stable tone); the leading tone is almost never doubled because two leading tones would both want to resolve up to the tonic, causing parallel octaves.
Why analysis and voicing go together
The central idea is that Roman numerals describe function while SATB describes realization, and the harmony questions test both. A numeral such as V6/5 tells you the chord is a dominant seventh in first inversion, which already implies how it should resolve; laying it out in four voices then forces you to choose a doubling, a spacing and a bass note that obey the voice-leading rules. The two skills reinforce each other: reading a passage and writing the numerals trains you to hear function, and spelling each numeral across four voices trains you to write idiomatic textures. This is the bridge from the chord-spelling topics of Unit 3 into the voice-leading work of Unit 4, where the numerals become progressions and the SATB layout is scored against strict rules.
Analyzing a chord
To analyze a chord, find the bass note and the other chord tones, stack them in thirds to name the root and quality, work out the root's scale degree in the key, choose the case to match the quality, and add the figure for the inversion.
Try this
Q1. What does a lowercase Roman numeral with a small circle indicate? [1 point]
- Cue. A diminished triad, such as vii (diminished) on the leading tone in a major key.
Q2. In SATB texture, which chord tone is usually doubled in a root-position triad, and which is almost never doubled? [2 points]
- Cue. The root is usually doubled; the leading tone is almost never doubled because two leading tones cause parallel octaves on resolution.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2021 (style)1 marksSection I (multiple choice, written). In C major, a chord built on the second scale degree (D, F, A) in root position is labelled by which Roman numeral? (A) II (B) ii (C) ii with a small circle (D) bIIShow worked answer →
The correct answer is (B) ii.
The diatonic chord on degree 2 of a major key is a minor triad (D, F, A in C major), so it takes a lowercase numeral, ii. Lowercase shows minor quality; the chord is in root position, so no figure is added.
(A) uppercase II would mean a major triad on degree 2, which is not diatonic. (C) the small circle marks a diminished triad, which the ii chord in major is not (the diminished diatonic triad is vii). (D) flat-II is a chromatic chord (the Neapolitan), not the diatonic supertonic. The trap is using uppercase out of habit; the case must match the chord's actual quality.
AP 2023 (style)3 marksSection II (free response, part-writing). In G major, spell the I chord in root position across four voices (SATB) with the root doubled, and state the pitch in each voice, keeping each voice in a singable range.Show worked answer →
A 3-point voicing question.
(1 point) The I chord in G major is G, B, D (root G, third B, fifth D).
(1 point) With the root doubled, the four voices use G (doubled), B and D. A workable close-position layout is bass G2, tenor D3, alto G3, soprano B3, which doubles the root (G in bass and alto) and includes the third (B) and fifth (D).
(1 point) Each voice stays in range: bass low, tenor and alto in the middle, soprano on top, with no voice crossing (soprano above alto above tenor above bass).
Markers reward including all three chord tones, doubling the root, and keeping the voices in order and in range. Omitting the third (B) or doubling the leading tone would lose marks; here the root G is the safe note to double.
Related dot points
- Topic 3.1 Triads: build a triad as three pitches stacked in thirds (root, third, fifth), and identify its quality as major, minor, diminished or augmented.
A focused answer to AP Music Theory Topic 3.1, covering the triad as stacked thirds (root, third, fifth), the four triad qualities (major, minor, diminished, augmented), how the third and fifth above the root define each quality, and the diatonic triads of a key, with a worked build.
- Topic 3.3 Seventh Chords: build a seventh chord by adding a seventh above the root, and identify its quality (major, dominant, minor, half-diminished, fully diminished).
A focused answer to AP Music Theory Topic 3.3, covering the seventh chord as a triad plus a seventh above the root, the five common qualities (major, dominant or major-minor, minor, half-diminished, fully diminished), how the triad and the seventh combine, and the diatonic sevenths of a key, with a worked build.
- Topic 3.2 Triad Inversions and Figures: identify root position, first inversion and second inversion triads, and label them with figured-bass symbols (no figure, 6, and 6/4).
A focused answer to AP Music Theory Topic 3.2, covering triad inversions (root position, first inversion, second inversion) named by the chord tone in the bass, the figured-bass symbols (no figure, 6, 6/4) and how figures measure intervals above the bass, with a worked inversion.
- Topic 4.2 SATB Voice Leading: apply the rules of range, spacing, doubling, smooth motion and tendency-tone resolution when writing four-part harmony.
A focused answer to AP Music Theory Topic 4.2, covering the four-voice ranges, the spacing rule (no more than an octave between adjacent upper voices), doubling guidelines, the ban on parallels and voice crossing, and resolving the leading tone and tendency tones, with a worked voicing.
- Topic 4.3 Harmonic Progression, Functional Harmony, and Cadences: explain tonic, predominant and dominant function, the normal direction of progressions, and the four cadence types.
A focused answer to AP Music Theory Topic 4.3, covering functional harmony (tonic, predominant, dominant), the normal flow tonic to predominant to dominant to tonic, and the four cadences (perfect authentic, imperfect authentic, half, plagal, with the deceptive cadence), with a worked cadence analysis.
Sources & how we know this
- AP Music Theory Course and Exam Description — College Board (2024)