Learning the Chords in a Key

Bill asks:
Can you tell me please what are the chords in the key of C, key of G, key of F, and key of D?
Well, I could just tell Bill what the chords are in each of those keys, but with just a little knowledge, anyone can figure out the chords in a key for themselves. Read this lesson on learning chords in a key for more info. Learning the Chords in a Key