Definitions length units, area units, and geometric shapes
Used in the book Mathematics in Nine Chapters

Chinese Pinyin Definition
chi Length unit: 1 Chi varies from 25 to 30 cm (10 to 12 inches). During much of the past 2000 years, it varied around 25 cm +/-.
See Ref.
B bu Length unit: Bu is the basic unit of length used in the book
1 bu = 3 chi
li Unit of length: 1 li = 300 bu
n B ji bu Unit of Area: 1 square bu = 1 bu x 1 bu
n ji li Area unit: 1 square li = 1 li x 1 li
= 375 mu
= 90,000 bu
a mu Area unit: 1 mu = 240 square bu
qing Area unit: 1 qing = 100 mu
fang tian Rectangular field = Rectangle
s guang width
q cong length
c gui tian Triangular area
xie tian Trapezoidal area
ji tian Right-angle trapzoidal area
yuan tian Circular area
P yuan zhou Circumference of circle
| yuan jing diameter of a circle
{ wan tian semi-circular area
hu tian Area of segment
xian chord
shi radius
Area of ring