Watch the Full Contact online guitar lesson by Brad Carlton from Chord Studies: Evolving Triads Vol. 1
This is another variation of the I - IV - V in A; however this time we are using only the first three strings. The first shape is a root position A triad which you can see comes right of the A form in the CAGED system. Next we move up to a D chord, second inversion and then finish up with a second inversion E for two measures. Throughout this example your first finger stays in contact with the third string.