Square Kilometer (km²)
The square kilometer, or km², is equal to one million square meters. It was designed for measuring large areas when the metric system was introduced. Square kilometers are often used in geography, maps, and environmental studies to represent the size of places such as cities, forests, and countries. For example, a country’s size is typically measured in square kilometers (km²). Its ease of use and simple conversions make it important for sharing global information.
Square Yard (yd²)
The square yard, or yd², is an area unit from the imperial system. It is the area of a square with one-yard sides and equals 9 square feet or 0.836127 square meters. Used first in England, the square yard was set as a standard in the 1900s. It is still used in the US and UK, particularly for real estate, carpets, fabrics, and sports fields. While most of the world now uses square meters, the square yard is still recognized and used in certain professions.