64 GREEK NUMERICAL NOTATION 
9 
method is clear from a passage of Heron, where he gives 4— 
as an approximation to ^/(100), and shows how he obtains it. 1 
Heron merely gives th§ working dogmatically, in concrete 
numbers, without explaining its theoretical basis, and we 
cannot be quite certain as to the precise formula underlying 
the operation. The best suggestion which has been made on 
the subject will be given in its proper place, the chapter 
on Heron. 
Heron, Metrica, iii. c. 20.