The golden section refers to dividing the whole into two parts, and the ratio of the larger part to the whole is equal to the ratio of the smaller part to the larger part, and the ratio is about 0.6 18. This ratio is recognized as the most aesthetic ratio, so it is called the golden section. The golden section is widely used in architecture, painting, music and other fields.

In ancient Greece, Pythagoras was walking in the street one day. Before passing the blacksmith's shop, he heard the sound of striking the iron, so he stopped to listen. He found that the blacksmith had a regular rhythm in striking iron, and the proportion of this sound was expressed mathematically by Pythagoras.

The golden section of human body:

There are many examples of golden section of human body, and 0. 18 is everywhere in human body structure.

For example, navel is the golden section of human body length, and knee is the golden section of human body length below navel. In the field of comparative oral anatomy, a six-year-old tooth with a ratio of 0.6 18 (the first molar erupted at the age of six) is "different" because of its large crown, many cusps, wide chewing area and firm root bifurcation.

It not only plays the most concentrated role in chewing food and bears the greatest chewing pressure, but also plays an important role in maintaining the correctness of the lower third of the face and the occlusal relationship between the upper and lower dental arches.

The most perfect human body: the distance from navel to sole/the distance from top of head to sole = 0.618; The most beautiful face: the distance from eyebrow to neck/the distance from the top of head to neck = 0.6 18.