Talking Theory About Am/C Pentatonic
For Am, the R [root] is A. The C is a ♭3 because the ‘normal C’ type tone to an A is a C♯ [it’s what’s in the A’s Major scale]. The D is a 4. The E is a 5. The G is a ♭7 because A’s normal G type tone in A Major is a G♯.
Both the C and G are lowered from what is ‘normal’ in A Major. We use a flat nomenclature regardless of the tone names. In this case, lowering these tones result in natural tones [because they are sharped in the Major]. See Derivative/Parallel. And, since the form is the same, the tone components have the same location in every key.
In a minor pentatonic, we are ‘missing’ the 2 & 6 tones. The scale is its own thing, but it can also be compared to a heptatonic. What’s ‘missing’? The 2 and the 6.
For C Major, the scale is simply a Major scale without a 4 & 7. The 4 & 7 create an interval of a tritone. It’s a tense type of interval. When it isn’t included, as with these pentatonic scales, the scale is more hollow and open.