The way to determine the length unit is to find a standard length as a reference, and then use this length to measure the length of other objects. The principle is to compare the lengths of different objects by using the corresponding relationship between the lengths of the same or equal ratio.

1 inch

Inch is a traditional unit of length used in Britain, the United States and other countries, which originated in ancient Rome. At that time, it was about 2.54 cm based on the width of human thumb. Later, after many revisions, it was finally determined that 1959 was exactly equal to 2.54 cm.

2 cm

The centimeter is the unit of length in the metric system, which is one hundredth of the meter. The metric unit was first put forward by France at the end of 18, with the aim of establishing a unified, simple and scientific system of weights and measures. As a fractional unit in the metric system, centimeter was also determined in this period.

3. Rice

The meter is the basic unit of length in the international system of units, and it is a common and recognized length standard in the world. The definition of meter has also undergone many changes, from the initial meridian of the earth to the standard ruler of platinum-iridium alloy, and now to a certain fraction of light propagation in vacuum. At present, the meter is defined as the distance traveled by light in vacuum 1/299792458 seconds.

The application significance of length unit in various fields

1, in medical field

The application significance of length unit lies in measuring human body size more accurately, which is helpful for medical diagnosis and treatment planning.

2. In the field of architecture

The application significance of length unit is to accurately measure and calculate the size and structure of buildings to ensure the stability and safety of buildings.

3. In the field of manufacturing

The application significance of length unit is to accurately measure and mark the dimensions of machine parts and tools to ensure the quality and performance of machines and tools meet the standards.

4. In the field of scientific experiments and engineering.

The application significance of length unit lies in the measurement and calculation of physical and chemical quantities, which is helpful to scientific research and technological development.

5. In the field of daily life

The application significance of length unit is to facilitate people to measure and calculate the length and improve people's quality of life and convenience.