Square Inch (in²)
The square inch, or in², is the smallest commonly used unit of area in the imperial system. It is the area of a square with one-inch sides and equals 6.4516 square centimeters. It originates from the inch and has been widely used in engineering, technical drawings, and manufacturing. Today, it is still good for small things like screens, machine parts, and prints. Most countries now use square centimeters, but the square inch is still used in areas where the imperial system is prevalent.
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.