The root of a chord is the note that gives the chord its name. In this case, the root is C.

The third of a chord is the note that is three scale degrees above the root. In this case, the root is G, so the third is B.

The fifth of a chord is the note that is five scale degrees above the root. In this case, the root is D, so the fifth is A.

A major triad is a chord that consists of a root, a major third, and a perfect fifth. In this case, the root is F, the major third is A, and the perfect fifth is C.

A minor triad is a chord that consists of a root, a minor third, and a perfect fifth. In this case, the root is B, the minor third is D, and the perfect fifth is F#.

An augmented triad is a chord that consists of a root, a major third, and an augmented fifth. In this case, the root is E, the major third is G#, and the augmented fifth is C#.

A diminished triad is a chord that consists of a root, a minor third, and a diminished fifth. In this case, the root is G, the minor third is Bb, and the diminished fifth is Db.

The chord symbol for a major chord is simply the letter name of the root. In this case, the root is C, so the chord symbol is C.

The chord symbol for a minor chord is the letter name of the root followed by a lowercase "m". In this case, the root is G, so the chord symbol is Gm.

The chord symbol for an augmented chord is the letter name of the root followed by a "+" sign. In this case, the root is D, so the chord symbol is Daug.

The chord symbol for a diminished chord is the letter name of the root followed by a "dim" or "o" symbol. In this case, the root is B, so the chord symbol is Bdim.

The chord progression I-IV-V in the key of C major consists of the chords C major, F major, and G major. These chords are the first, fourth, and fifth chords in the C major scale.

The chord progression ii-V-I in the key of G major consists of the chords Am, D, and G. These chords are the second, fifth, and first chords in the G major scale.

The chord progression vi-ii-V-I in the key of D minor consists of the chords Bm, Dm, G, and D. These chords are the sixth, second, fifth, and first chords in the D minor scale.

The chord progression I-vi-IV-V in the key of A major consists of the chords A major, F# minor, D major, and E major. These chords are the first, sixth, fourth, and fifth chords in the A major scale.