There are two commonly used root 5 seventh bar chord shapes based upon these two open A7 chord shapes. The following diagram illustrating shape 2 of A7 is usually played using four fingers. However, when it is used to form a bar chord, the third finger bars across the three notes on the second fret.
Here are three of the root 5 shapes used in the next exercise.
A7
A7
The following progression combines root 5 and root 6 seventh chord shapes. For the root 5 E7 and D7 chords play shape 1 the first time through the progression and for the repeat play shape 2.