The Original Drawings:
Mercury

0 is 0.000000 the origin, the Sun.

A is 0.792893..., perihelion Mercury, 2 minus .5 (sqrt 2 + 1)

B is 1.000000..., mean orbital dist. Mercury, .5 (sqrt 1 + 1)

C is 1.207106..., aphelion Mercury, .5 (sqrt 2 + 1)

D is 1.414213..., square root 2. (sqrt diameter Mercury)