$1 : \frac{1 + \sqrt{5}}{2} \fallingdotseq 1 : 1.618$

$360 \times \frac{1}{1 + \frac{1 + \sqrt{5}}{2}} \fallingdotseq 137.51$

参考 » http://gakuen.gifu-net.ed.jp/~contents/museum/golden/page62.html

$1 : \sqrt{2} \fallingdotseq 1 : 1.414$