Zhao Shuang's Han Dynasty Proof of the Pythagorean Theorem

This GeoGebra construction dynamically illustrates Zhao Shuang’s (also known as Zhao Junqing) classical geometric proof of the Pythagorean Theorem from the Han Dynasty. It visually demonstrates the relationship a² + b² = c² using a dissection-and-rearrangement method based on the 'Xian Tu' (String Diagram). The example relies on fundamental concepts of Euclidean geometry, including area equivalence, congruence, and right triangle properties. Constructed using basic GeoGebra commands such as Segment, OrthogonalLine, and Point, it defines numerous points (A, B, C, ..., N, O, etc.) and segments (a_1, b_1, c_2, etc.) to accurately replicate the historical diagram. Ideal for middle school mathematics education, this model supports teaching geometric proof, integrating history of mathematics, and fostering inquiry-based learning.