In the pentagram, the Pythagoreans found all proportions well-known in antiquity: arithmetic, geometric, harmonic, and also the well-known golden proportion, or the golden ratio. ... Probably owing to the perfect form and the wealth of mathematical forms, the pentagram was chosen by the Pythagoreans as their secret symbol and a symbol of health. - Alexander Voloshinov [As quoted in Stakhov]
Alexey Stakhov, Mathematics of Harmony
geometry, golden-ratio, harmony, history-of-mathematics, pentagram, pythagoreans, sacred-geometry