A kilometer (km) is a unit of length used in the metric system of measurement. It is equal to one thousand meters, which is the base unit of length in the International System of Units (SI). Therefore, 1 kilometer is equal to 1,000 meters, 100,000 centimeters, 1,000,000 millimeters, or 0.621371 miles.
Kilometers are commonly used for measuring longer distances on Earth, such as the length of roads, the distance between cities, and the dimensions of geographical features like rivers, mountains, and coastlines. They are also used in various sports and outdoor activities, such as running, cycling, and hiking, to express distances. Kilometers are a convenient unit of measurement for everyday use in many countries around the world that use the metric system.
The "archin" is an obsolete unit of length that was historically used in Russia and other parts of the former Soviet Union. The length of an archin varied by region and over time, but it was typically around 28 inches or approximately 71 centimeters. In some regions, an archin could be slightly shorter or longer.
The archin was used for measuring cloth, textiles, and sometimes land. Like many traditional units of measurement, it has largely been replaced by more standardized systems, such as the metric system, in modern times. While the archin is no longer commonly used for official measurements, it may still be encountered in historical or traditional contexts in Russia and other former Soviet states.