dependence between diameter and square based on the same diagonal
( 4 * d / pierw(2) ) / ( Pi * d ) = 4 / ( pierw(2) * Pi ) = 0.9
I think what the OP is saying is that the ratio of the perimeter of a square of diagonal length D to the circumference of a circle with diameter D is:
$\displaystyle \frac {P_{square}}{P_{circle}} = \frac {4 \frac D {\sqrt 2}}{\pi D} = \frac 4 {\pi \sqrt 2} = 0.9003.. $
His notation "pierw(2)" apparently means "square root of 2." As to why he posted this - I have no idea.