1kilometer

A kilometer, abbreviated km, is a unit of length in the metric system equal to 1,000 meters. The prefix kilo- denotes a factor of 1,000, so the kilometer is commonly used to express distances on land, travel routes, and in many scientific and everyday contexts.

Origin and definition: The metric system was developed in France in the 18th century. The kilometer, formed by applying the prefix kilo- to the base unit meter, denotes 1,000 meters. In the International System of Units (SI), the kilometer is a derived unit used for larger lengths.

Common uses: Distances between cities or along roads are typically given in kilometers. Road speeds are described in kilometers per hour (km/h). Athletic race distances, such as 5-kilometer and 10-kilometer events, are widely reported. In scientific contexts, kilometers are used for terrestrial measurements where meters would be impractically short, though for very small scales meters or centimeters may be preferred.

Conversions: 1 km = 1,000 m; approximately 0.621371 miles; 1 mile = 1.609344 km; 1 km ≈ 3,280.84 feet; 1 km = 1093.6133 yards; 1 km = 100,000 cm; 1,000,000 mm.