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五边形的东西生活中很多,像公园的五角亭就是一个好例子.那么五角尖尖的凉亭是怎样造出来的呢? 古人有句口诀“一六中间坐,二八分两旁.”这就是用直尺画出正五边形的近似形的秘诀. “一六中间坐”,就是取1个单位长的线段AB,设其为1,然后取其中点F,作垂直线FGD,长度为1.6,其中FG为1,GD为0.6.“二八分两旁”,就是通过 G作平行于AB的线段CE,且 EG=GC=0.8,作五边形AB-CDE,就是一个近似的正五边形.
There is a lot of pentagonal life. The pentagonal pavilion like a park is a good example. How did the five-cornered pavilion come into being? The ancients had a mouthful: “One six sits in the middle, twenty-eight points on both sides.” This is Use a ruler to draw the secret of the approximate shape of the regular pentagon. “Six in the middle” is to take a line segment AB of a unit length, set it to 1, and then take its midpoint F, as the vertical line FGD, the length is 1.6, in which FG is 1, GD is 0.6. “Two points on both sides” is the segment CE that is parallel to AB through G, and EG=GC=0.8. It is a pentagon AB-CDE, which is an approximate positive five. Edge shape.