don steward
mathematics teaching 10 ~ 16

Wednesday, 11 April 2018

ancient Chinese maths in right angled triangles

the 'Jiuzhang Suanshu' ('the nine chapters on the mathematical art') appears to be problems illustrating general techniques that were collected together over time

much light is shed on the processes and justification for the methods used in this important document by Liu Hui (around 260 CE) but he indicates that the ideas date back to before 210 BCE

the ninth (final) chapter is devoted to the 'Gougu rule' (otherwise known as Pythagoras' rule) and to problems involving similar triangles, connected to surveying

the 'gou' is the shortest side, 'gu' the middle side and 'xian' the longest side in a right angled triangle

most of the 24 problems in this chapter have a practical origin

measures are a simple decimal structure

a powerpoint suggests approaches to each problem
diagrams are included from some translations but were lost in the original

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