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Golden Ratio and Fibonacci Overview

Aug 31, 2025

Overview

This lecture introduces the Golden Ratio and Fibonacci sequence, highlighting their appearances in mathematics, art, nature, architecture, music, and human design.

Introduction to the Golden Ratio and Fibonacci Sequence

  • The Golden Ratio (approximately 1.618), denoted as "phi," is a proportion found in mathematics, art, and nature.
  • The Fibonacci sequence is a series where each number is the sum of the two preceding numbers (e.g., 1, 1, 2, 3, 5, 8).
  • Fibonacci numbers are commonly found in natural and man-made structures.

Architectural Examples

  • The Great Pyramids of Giza incorporate the Golden Ratio in their triangular geometry and grid-based placement, forming golden spirals from an aerial view.
  • The Taj Mahal's architecture uses the Golden Ratio (phi matrix) in its base and other buildings within its premises.

Art and Design

  • Leonardo da Vinci’s Mona Lisa applies golden rectangles to facial and body proportions, fitting the golden spiral.
  • Da Vinci's Vitruvian Man and The Last Supper also feature the Golden Ratio.

Nature and the Cosmos

  • Spiral galaxies, including the Milky Way, form golden spirals; even hurricanes show this pattern.
  • The radius of the Moon plus Earth equals the square root of five, relating to phi in their spatial relationship.
  • Flower petals often occur in Fibonacci numbers; rose petal and pine cone arrangements show golden spirals.
  • DNA dimensions (34 by 21 angstroms) are both Fibonacci numbers; DNA cross-sections show phi relationships.

Music and Human Perception

  • Music compositions (e.g., Beethoven’s Fifth Symphony, Mozart’s sonatas) utilize the Golden Ratio for timing and structure.
  • Human facial symmetry is perceived as attractive due to alignment with the Golden Ratio; used in plastic surgery and facial recognition software.

Advertising, Branding, and Web Design

  • Advertisers use faces and designs following the Golden Ratio to attract customers.
  • Logos (e.g., Toyota, Pepsi) and web templates often use golden rectangles or grids for visual appeal.

Anatomy of Living Things

  • The human body shows the Golden Ratio in proportions (head, shoulders, fingertips, forearm).
  • The number five recurs in human anatomy (five senses, fingers, etc.) and in the segmented bodies of insects.

Key Terms & Definitions

  • Golden Ratio (phi, ≈ 1.618) — a mathematical proportion often found in nature, art, and architecture.
  • Fibonacci Sequence — a series where each number equals the sum of the two preceding numbers.
  • Golden Spiral — a spiral that increases in size by the factor of the Golden Ratio for each quarter turn.

Action Items / Next Steps

  • Explore your surroundings and identify examples of the Golden Ratio or Fibonacci sequence in objects or designs.
  • Review the definitions and examples of the Golden Ratio for further study.