Figure 4 sqrt2/4 is truncated to nine digits and rationally approximated.

fp2ratio .353553391

0.353553391:

          1 / 2          +41.4%
          1 / 3           -5.7%
          5 / 14          +1.0%
          6 / 17          -0.17%
         29 / 82          +0.030%
         35 / 99          -0.0051%
        169 / 478         +0.00088%
        204 / 577         -0.00015%
        985 / 2786        +0.000026%
       1189 / 3363        -0.0000045%
       5741 / 16238       +0.00000064%
       6930 / 19601       -0.00000025%
      19601 / 55440       -0.000000015%
     104935 / 296801      -0.0000000021%
     124536 / 352241      +0.00000000062%
     354007 / 1001283     -0.00000000018%
     478543 / 1353524     +0.000000000024%
    2746722 / 7768903     -0.0000000000027%
    3225265 / 9122427     +0.0000000000013%
    5971987 / 16891330    -0.00000000000050%
    9197252 / 26013757    +0.00000000000014%
   24366491 / 68918844    -0.000000000000016%
   82296725 / 232770289   +0.0000000000000012%
  353553391 / 1000000000  Exactly!