Golden section

Also called golden ratio, golden mean, divine proportion, φ, phi

The division of a line so that the whole is to the larger part as the larger is to the smaller; the ratio φ = (1 + √5)/2 ≈ 1.618. Also called the golden ratio, golden mean or divine proportion.

Rules that use the word

Regulating lines. Check the proportions of a façade with a few geometric lines (diagonals of similar rectangles, the golden section) so that its parts share one order and nothing is arbitrary.

The golden section. To divide a line in extreme and mean ratio, make the whole stand to the larger part as the larger part to the smaller; the ratio is φ = (1 + √5)/2 ≈ 1.618. Construct the golden rectangle by swinging the line from the midpoint of a square’s side to its far corner.

Measure before you believe. Treat claims that a building embodies the golden section with suspicion unless the designer’s own writings or drawings say so and careful measurement agrees; a ratio near 1.6 is found somewhere in almost anything.

The Modulor. Take the height of a man (183 cm) and of his raised hand (226 cm) and divide each by the golden section, again and again, to obtain two interlocking series of dimensions for every part of a building.

Where it appears in the book

In the chapters Proportion and Number.

Nearby in the glossary

Giardino segreto · Girih · Giwa · Going · Gong · Gopuram · Groin · Groin vault