周三径一 / 周三徑一

zhōu​sān​jìng​yī

pi approximation

the ancient Chinese approximation of pi as 3 to 1 (circumference is three, diameter is one)

中国古代数学家用“周三径一”来简略计算圆的周长。

created sense Mar 4, 2026, 02:25 AM