Golden Ratio is obtained, when a line is divided into the long part A and the short part B. The division has to be done in a way that A plus B divided by A is equal to A divided by B. Golden Ratio is indicated by the Greek letter phi φ and has the approximate value 1,618. An interesting feature of the Golden Ratio is its definition: φ = 1 + 1 / φ.
Furthermore, it is believed that the Golden Ratio is related to the Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21... Each number in the Fibonacci sequence is the sum of the previous two numbers (for instance, 21 = 8 + 13). If you divide the last number of the Fibonacci sequence by the previous one, we obtain approximately φ (for instance, 21 / 13 = 1.61...).
In arts and architecture, it is considered that a rectangle with edges 1 and φ has an aesthetic shape (pleasing to the eye). The Golden Ratio appears in nature for example in the spiral shells, sunflowers, pinecones, spiral galaxies or hurricanes. Hence, it is a cross-cutting phenomenon that covers many different fields.