  In this work we characterized a X-ray position sensitive gaseous detector
based in a triple stack of gas electron multipliers (GEM). The readout circuit
is divided in 256 strips for each dimension and using a resistive chain
interconnecting the strips, we are able to reconstruct the radiation
interaction points by resistive charge division. The detector achieved gains
above $10^4$, energy resolution of 15.28% (FWHM) for 5.9keV X-rays, and
position resolution of 1.2mm, while operating in Ar/CO$_2$(90/10) at
atmospheric pressure.
