Construct triads and seventh chords, label them with Roman numerals and chord symbols, recognise inversions, and analyse progressions and cadences.

What this dot point is asking

Building triads

A triad is three notes a third apart: a root, a third and a fifth. The quality depends on the two thirds. A major triad is a major third then a minor third (C E G). A minor triad is a minor third then a major third (C E flat G). A diminished triad is two minor thirds (C E flat G flat). An augmented triad is two major thirds (C E G sharp).

In any major key the triads built on each scale degree have a fixed pattern of qualities: I, IV and V are major, ii, iii and vi are minor, and vii is diminished. Knowing this pattern lets you harmonise a melody quickly without rebuilding every chord from scratch.

Seventh chords

Adding a third above the fifth makes a seventh chord. The dominant seventh (V7) is the most important: a major triad with a minor seventh, for example G B D F in C major. It contains a tritone between the third and seventh that resolves inward to the tonic, which is why V7 to I is such a strong progression. Other sevenths include the major seventh (bright, jazzy) and the minor seventh (smooth, common in pop and jazz).

Labelling: Roman numerals and chord symbols

There are two labelling systems. Roman numerals show a chord's function within a key: upper case for major (I, IV, V), lower case for minor (ii, vi), and a small circle for diminished (vii). This is the language of analysis because it shows the harmonic role regardless of key.

Chord symbols name the actual chord: C, Dm, G7, Fmaj7. These appear in lead sheets and popular music. You should be fluent in both, because the exam may give you one and ask for the other.

Inversions

A chord is in root position when its root is the lowest note. It is in first inversion when the third is lowest, and second inversion when the fifth is lowest. Figured bass shows inversions with numbers: 6 for first inversion, 6/4 for second inversion of a triad, and 7, 6/5, 4/3, 4/2 for the inversions of a seventh chord. In Roman-numeral analysis you write Ib or V6/5. Inversions smooth the bass line and create different colours from the same chord.

Progressions and cadences

Harmony moves between functions: tonic (I, stable home), subdominant (IV, departure) and dominant (V, tension that wants to resolve). A cadence is the chord pair that ends a phrase. The perfect (authentic) cadence is V to I and sounds finished. The plagal cadence is IV to I, the "amen" sound. The imperfect (half) cadence ends on V and sounds unfinished, needing continuation. The interrupted (deceptive) cadence goes V to vi, surprising the ear by avoiding the expected tonic.

Hearing harmony

Aural harmony tasks ask you to identify chord qualities, simple progressions and cadence types. Listen first to the bass line, which often outlines the roots. Then judge whether each chord sounds major or minor, and whether the phrase ends with a sense of completion (perfect or plagal) or suspension (imperfect or interrupted). Singing the bass and the roots aloud trains this skill faster than passive listening.