The second executable tuple uses native dimensions 3840×2160 and a visible diagonal of 31.5 inches. Labels such as “4K” are not used in the arithmetic.
Pixel diagonal: 4,405.814340 px
The integer inputs produce √(3840²+2160²), displayed as 4,405.814340 px after six-place rounding.
Density: 139.867122 PPI
4,405.814340÷31.5 gives 139.867122 PPI, 55.065796 px/cm and approximately 0.181601 mm pixel pitch.
Panel rectangle: 27.454629×15.443229 in
That is approximately 69.734759×39.225802 cm, ratio 16:9, 8,294,400 total pixels and 8.2944 MP.
How to interpret the result
This density describes the panel itself, not the operating system scaling setting or the distance from which it will be viewed. Two displays with the same 3840×2160 resolution can therefore have different PPI values when their diagonals differ. Use the visible panel diagonal from the specification and compare like-for-like inputs.