<!-- Origin Article URL: http://www.wretch.cc/blog/cderty/26551121 --> <img src="http://f10.wretch.yimg.com/cderty2006/1/1963056999.jpg" alt=""/><br/> <br/> 二丈木長三尺圍,<br/> <br/> 葛生其下纏繞之,<br/> <br/> 徐徐纏繞七周遍,<br/> <br/> 葛梢卻與木梢齊,<br/> <br/> 試問先生能算者,<br/> <br/> 葛長多少請君題。<br/> <br/> <br/> <br/> <br/> <br/> <br/> <br/> <br/> <br/> <br/> Ans:<br/> <br/> <img src="http://f10.wretch.yimg.com/cderty2006/1/1963057000.jpg" alt=""/><br/> <br/> 每解一周,則形成一小勾股形<br/> <br/> 即木長AC=20尺為勾,圍之BC=<img src="http://f10.wretch.yimg.com/cderty2006/1/1963057001.jpg" alt=""/>為股<br/> <br/> 根據勾股定理,得葛長為弦<img src="http://f10.wretch.yimg.com/cderty2006/1/1963057002.jpg" alt=""/>