A chord, as discussed in the chapter on scales, may be built upon any note of a scale. Thus a heptatonic scale allows seven basic triads built up using the first, third and fifth notes of that degree. The starting note of each scale degree of the scale becomes the root note of its own chord. This is different from the concept of chords being formed from a scale using the notes of that scale, keeping the root unchanged. Now, a chord built upon the note C is an C (something) chord. So, the seven chords thus formed will have different root names.
Before continuing, do read the posts on Roman numeral notation of chords
continue to common chord progressions....
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