Chords are usually made up of combinations of major and minor third intervals. As mentioned previously, the simplest chords are triads made up of three notes. There are four basic types of triads: major, minor, augmented and diminished. Examples of each of these are shown next, along with the appropriate chord formula and intervals.
Using the formulas on the previous page, you can easily work out the notes for any type of triad beginning on any note. E.g., to form a A major chord you would begin with the note A and then add a major 3rd (four semitones) above it (C#) and then a minor 3rd (three semitones) above that (E). To form a D# diminished chord, you would begin with a D# note and then add a minor 3rd above it (F#) and then another minor 3rd above that (A). To help you become more familiar with the four types of triads, write the required notes above the root notes shown, to create the triads indicated.