%!

% scale to inches
72 dup scale
% move the origin to page centre
4.25 5.5 translate
% reset the line width to one Adobe point
% by default it is 1 current unit 
1 72 div setlinewidth

% draw a circle as a polygon of N sides
/N 64 def
newpath
1 0 moveto
N {
% angles are measured in degrees
360 N div rotate
% after a coordinate transformation
% all coordinates are in the new system
1 0 lineto
} repeat
stroke