The golden ratio is a mathematical ratio, approximately equal to 1.618, often denoted by the Greek letter φ (phi). It appears in various aspects of art, architecture, and nature, where it is believed to create aesthetically pleasing proportions. When a line is divided into two parts, the ratio of the whole line to the longer part is the same as the ratio of the longer part to the shorter part. This ratio can be found in famous works, such as the Parthenon in Greece and the paintings of Leonardo da Vinci. In nature, it can be observed in the arrangement of leaves, the patterns of shells, and the branching of trees, showcasing its universal presence.