According to multiple sources the following problem would be found in Suanfa tong zong (like on cut-the-knot)
Two reeds of equal height project 3 syaku above the surface of a pond. If we draw the top of one reed 9 syaku in the direction of the shore so that the top is just touching the surface of the water, find the depth of the pond.
(Cut-the-knot claims the book contains the illustration, but another source claims the illustration is Japanese)
Anyhow: I assume Syaku would be an ancient Chinese unit of measurement. But I couldn't retrieve any information on this unit. How is it defined, how much would 1 syaku be in modern units of measurement?
I tried digging up the original problem, but when searching for the original (or any later reprints) I get stuck on the Chinese symbols. Could anyone help me out?
Not sure if "Chinese Language" is the right place for this question. I've been thinking about or "History of Science and Mathematics", but I think the probability of someone owning "Suanfa tong zong" would be the greatest here (?)