As we remember, Baalbek and Lalibela, together with St. Petersburg, lie on the same line with the error 0.35 degree.
Turning nonagon on 9 degrees clockwise, we see that between these lines and the direction to Tiwanaku are100 degrees. In the case of Baalbek error is 0.31 degree, in the case of Lalibela it is 0.66 degree.
As we remember from the hexagram direction to Baalbek and Lalibela, is perpendicular to one to Stonehenge. Therefore, azimuth of Tiwanaku differs from one to Stonehenge on 10 degrees with the error less than one degree. You can see it on the interactive map at the end of this page.
Turning nonagon on 6.3 degrees counter-clockwise we find that the angle between the azimuths of the Por Bajin and of Vera island is 20 degrees, with the error 0.2.
Having turned nonagon on 7 defrees counter-clockwise we obtain the exact azimuth of Nan Madol from which is away on 100 degrees azimuth of Teotihuacan with the error 0.11 .
Thus, coming out to the Palace Square with drawn nonagon, we can determine very accurately the direction to Teotihuacan without any instruments and measuring systems.
To do this, you need to superpose one of the nonagon axes with marking on the square parallel to the Winter Palace and count out counter-clockwise against 100 degrees.