Da Inglese a Italiano Scienze Matematica e Statistica side-and-diagonal number progression

Let’s think like Heron and start with the circle calculations. If
we want to make them easier, it would make much more sense to set
the diagonal, and thus the diameter of the dome, at 140 feet. 140 is a
multiple of 7, and thus compatible with the 22/7 approximation of π.
If the diagonal was going to be 140 feet, Isidor and Anthemius
would have needed to tell the foreman what the length of the square’s
sides needed to be in order for him to begin the process of construction.
They probably did this using a Pythagorean trick called the side-anddiagonal
number progression, which gives an approximation for the
factor √2.