# Arima Yoriyuki

(Redirected from Yoriyuki Arima)
Arima Yoriyuki (有馬 頼徸?, December 31, 1714 – December 16, 1783) was a Japanese mathematician of the Edo period. He was the lord of Kurume Domain and approximated the value of $\pi$ and its square, $\pi^2$. In 1766, he found the following rational approximation of pi, correct to 29 digits:[1][2]
$\pi\approx\frac{428224593349304}{136308121570117}=3.14159265358979323846264338327(569...)$
1. ^ "Collection of approximations for $\pi$". Retrieved 2008-04-04.