The Golden Rectangle

Golden Mean

In this photo they're using the mathematical equation of golden mean, by placing her body is certain positions. Golden mean makes the golden rectangle.
The Golden Rectangle: Greek ideal of a perfectly proportioned rectangle using golden mean. 
Garn, Jake. "Golden Mean | Jake Garn Photography." Golden Mean | Jake Garn Photography. Jake Garn, n.d. Web. 04 Sept. 2012. <http://jakegarn.com/tag/golden-mean/>.