The Golden Ratio, represented by the Greek letter Phi (approximately 1.618), has been a guiding principle in art and architecture for centuries. It is a mathematical ratio found in nature that is believed to be aesthetically pleasing to the human eye. In the world of art, it is often applied through the 'Golden Rectangle' or the 'Fibonacci Spiral.' Famous works like the Parthenon in Athens and Leonardo da Vinci's 'The Last Supper' are thought to utilize these proportions to create a sense of balance and harmony. Renaissance artists referred to it as the 'Divine Proportion.' In 'The Vitruvian Man,' Leonardo explored the mathematical proportions of the human body, asserting that a perfectly proportioned human would fit within a circle and a square based on these ratios. While some modern historians debate the extent to which ancient artists used it consciously, the Golden Ratio remains a fundamental concept taught in art schools to help students master composition and focal points.