Euclid, an ancient Greek mathematician, defined the vertical ruler in his book Elements of Geometry. Euclid was one of the founders of geometry. He defined various geometric concepts in detail in Elements of Geometry, including vertical ruler.

Euclid defined in the Elements of Geometry that when a straight line intersects another straight line, its intersection point is called vertical foot. This definition is still widely used in mathematics and geometry.

Euclid also proved the vertical leg theorem in the Elements of Geometry, that is, after passing a point, there is only one straight line perpendicular to the known straight line. This is also an important property of vertical foot, which is widely used in mathematics and practical application.

In addition to playing an important role in geometry, vertical foot has applications in other fields. For example, in architecture, vertical ruler is used to determine the position of vertical line, while in mechanical parts, vertical ruler is used to describe the verticality of parts.

Application of vertical foot in life;

1. Architectural design and construction: In architectural design and construction, vertical footing is an important concept. For example, vertical feet play a key role in determining the vertical line of buildings. The vertical line of the building must pass through the vertical feet of two opposite sides of the building to ensure the verticality and stability of the building. In addition, the vertical foot can also be used to determine the verticality of the wall and the relative position of doors and windows.

2. Manufacturing and processing of mechanical parts: Vertical foot is an important geometric parameter in manufacturing and processing of mechanical parts. For example, to manufacture cylindrical parts, it is necessary to determine that the axis of the cylinder is perpendicular to the bottom surface, and then the position of the axis can be determined by vertical feet. In addition, in the process of machining, the vertical foot can also be used to determine the position and direction of machining.

3. Road and bridge construction: In road and bridge construction, vertical ruler also has important applications. For example, when determining the relative position of two piers of a bridge, it is necessary to determine the verticality and stability of the piers by vertical feet.