A student builds a chord by stacking a minor third (3 semitones) from C to E♭, then a major third (4 semitones) from E♭ to G. What chord has she built?
AC major, because the top and bottom notes (C and G) form the same interval as in C major
BC minor, because the bottom interval is a minor third
CC diminished, because the chord contains a flattened note (E♭)
DNeither major nor minor — stacking a minor third below a major third does not produce a standard triad
C minor is built with a minor third on the bottom (C to E♭, 3 semitones) and a major third on top (E♭ to G, 4 semitones). The outer interval C to G is a perfect fifth (7 semitones), the same as in C major. The chord is C minor precisely because the bottom third is minor — this is the only structural difference between C major (C-E-G) and C minor (C-E♭-G). The presence of E♭ does not make a chord diminished; diminished triads have a diminished fifth (6 semitones), not a perfect fifth.
Question 2 Multiple Choice
What interval separates the root and fifth of a minor triad?
AA diminished fifth (6 semitones), which gives minor triads their darker sound
BA minor fifth (6 semitones), equivalent to a tritone
CA perfect fifth (7 semitones), the same interval as in a major triad
DIt depends on the root note — some minor triads have perfect fifths, others have diminished fifths
Both major and minor triads span a perfect fifth (7 semitones) from root to fifth. This is the most common misconception about minor triads — the 'darkness' or 'sadness' of minor is caused by the minor third on the bottom (3 semitones), not by any alteration to the fifth. A diminished fifth (6 semitones) appears only in a diminished triad, which is a different chord type entirely. Checking the outer interval first is a reliable error-catching step: if it's not a perfect fifth, something has gone wrong.
Question 3 True / False
A minor triad differs from a major triad built on the same root because the minor triad has a diminished fifth instead of a perfect fifth.
TTrue
FFalse
Answer: False
Both major and minor triads have a perfect fifth (7 semitones) from root to fifth. The only structural difference is the quality of the bottom third: major triads use a major third (4 semitones) from root to middle note, while minor triads use a minor third (3 semitones). The middle note shifts by one semitone (e.g., E in C major vs. E♭ in C minor), but the top note (the fifth, G) stays the same. Diminished triads are a separate category with an actual diminished fifth.
Question 4 True / False
Both a C major triad and a C minor triad contain the note G as their top note (fifth).
TTrue
FFalse
Answer: True
C major = C-E-G and C minor = C-E♭-G. The fifth (G) is the same in both because both chords span a perfect fifth (7 semitones) from the root C. The only difference is the middle note: E (major third, 4 semitones above C) in C major versus E♭ (minor third, 3 semitones above C) in C minor. This illustrates that the outer interval is shared; the quality of the inner third determines major vs. minor.
Question 5 Short Answer
Both a major triad and a minor triad built on the same root span a perfect fifth on the outside. If the fifth is the same, what creates the perceptual difference between major and minor — and where exactly does that difference come from?
Think about your answer, then reveal below.
Model answer: The difference comes entirely from the middle note — specifically, which type of third sits on the bottom. In a major triad, the major third (4 semitones) is on the bottom; in a minor triad, the minor third (3 semitones) is on the bottom. This single semitone shift of the middle note changes the internal structure of the chord despite leaving the outer interval unchanged, producing the characteristic bright (major) versus dark (minor) contrast.
Understanding that the fifth is shared while the third differs is the key structural insight. It explains why the two-step check works: verify the perfect fifth first (both types pass), then check the bottom third (4 semitones = major, 3 semitones = minor). It also explains why beginning students misidentify minor triads as having diminished fifths — they hear the darker sound and assume the outer interval must differ, when in fact the difference is entirely interior.