數學IQ题

圖片參考：http://d.yimg.com/mt/nimage/b7673b80e29b3bd4

把六支火柴砌成一正4面體,4個面成為四個等邊三角形。

Four sides(matches 1 to 4) of a parallelogram of internal angles 60 and 120.
5th match joining the obtuse corners.
6th match joining the mid-points of two parallel matches.

2010-02-26 07:27:27 補充：
Two isosceles triangles (actually equilateral trianges of 60) formed between the 5th match.
Two smaller ones (equilateral triangles of side length of half match length) firned by the intersecting 5th and 6th matches and two parallel matches.

2010-02-26 07:31:41 補充：
I hope my above description can be visualised!
Please comment as I think no submitted answers above meet the requirements including (補充要)平面, otherwise 六支火柴砌成一正4面體 is correct.

2010-02-26 07:33:52 補充：
Sorry, 003 意見 should be :
Two isosceles triangles (actually equilateral trianges of 60) formed besides the 5th match.
Two smaller ones (equilateral triangles of side length of half match length) formed by the intersecting 5th and 6th matches and two parallel matches.

等腰三角形做底的立體三角形

But both of them have the same length ....

口
裹面加X
perhaps
i don't sure