http://cache.baidu.com/c?word=%D3%C3%3B%C8%F4%B8%C9%3B%B8%F6%3B%B5%C8%D1%FC%3B%CC%DD%D0%CE%3B%C6%B4%3B%D2%BB%B8%F6%3B%C1%E2%D0%CE&url=http%3A//www%2Exuexibao%2Ecom/Article/Print%2Easp%3FArticleID%3D216&b=0&a=34&user=baidu
能拼成菱形,先用三个拼成等边△ABC,再用三个拼成等边△ACDhttp://cache.baidu.com/c?word=%D3%C3%3B%C8%F4%B8%C9%3B%B8%F6%3B%B5%C8%D1%FC%3B%CC%DD%D0%CE%3B%C6%B4%3B%D2%BB%B8%F6%3B%C1%E2%D0%CE&url=http%3A//www%2Exuexibao%2Ecom/Article/Print%2Easp%3FArticleID%3D216&b=0&a=34&user=baidu 有图