德国杰出的天文学家开普勒称“黄金分割”为几何学中的瑰宝。“黄金分割”亦称“黄金律”、“中外比”。把长为l的直线分成两部分,使其中一部分对于全部的比等于其余一部分对于这部分的比,即x:l=l-x:x,这样的分割称为“黄金分割”,x=(5~(1/2)-1)/2=0.618。也就是说分成的两部分的直线段的比例数是1与1.618。早在1509年,威尼斯人卢卡·帕契奥里发表过《上帝规定的比例》一书。他的朋友辽奥纳多·达· Kepler, a distinguished German astronomer, called the “Golden Section” a gem in geometry. “Golden Section” also known as “golden rule”, “Sino-foreign ratio.” Divide the straight line of length l into two parts so that the ratio of one part to the whole is equal to the ratio of the remaining part to the part, ie, x: l = lx: x. Such a partition is called the golden section, x = (1/2) -1) /2=0.618. That is to say the ratio of the straight segments divided into two parts is 1 and 1.618. As early as 1509, Venetian Lucca Pachello published a book entitled “Proportion of God”. His friend, Leonardo Da