#4
ok... so wuts your question? do you want every little bit explained cause that would take alot of time. i would suggest is to pick up fretboard logic by bill edwards it will pretty much tell ya nething you need to know
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#6
It think maybe he meant: What chords are enharmonic to which key?

Well, as you know, a major scale has seven different notes. We'll use D Major as an example.
D E F# G A B C# D
You can build a chord from each of these notes, and the formula is easy: 1,3,5. If you start on a note, you include the third and fifth (counting from the root), and you have your chord.
Starting on D: D F# A = D Major
Starting on E: E G B = E Minor
Starting on F#: F# A C# = F# Minor.
etc

Do this with all seven notes, and you have the chords that fit within D Major. Do it with the notes of any other key, and you'll find the chords that go with that.