Every fingering that fits a hand
2100
open
210x
open
2404
easy
2104
easy
2454
moderate
What is true of it
A is A, C♯ and E — 1, 3 and 5 counted from A.
On an instrument that cannot reach all 3, the 5 goes first, in that order.
The easiest of the 5 fingerings below is 2100: 2 fingers, held at the 1st fret.
2 of them use open strings, which is what makes a shape quiet to change to.
Where its notes are on the neck
The brass dots are A, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
A/C♯
x100
A/E
999x
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.