The "square foot (US survey)" is a unit of area used in the United States primarily for land surveying and mapping purposes. It differs from the standard square foot because it is based on the U.S. survey foot, which is a historical unit of length used in land surveying in the United States. The U.S. survey foot is slightly different from the international foot.
One square foot (US survey) is equal to approximately 0.0929034119223 square meters (m²) or about 0.111111 square yards (yd²).
This unit is used in various land-related applications, particularly in the United States, where the U.S. survey foot and the square foot (US survey) are still employed for legal and historical reasons in certain land surveys and property descriptions. It's essential to be aware of the specific units being used when dealing with land measurements to avoid any discrepancies or errors.
A square kilometer (often abbreviated as km²) is a unit of area in the International System of Units (SI). It represents a square with sides that each measure 1 kilometer in length.
One square kilometer is equal to 1,000,000 square meters (m²) because there are 1,000 meters in a kilometer, and when you square that length, you get 1,000 * 1,000 = 1,000,000 square meters.
To visualize the size of a square kilometer, you can imagine a square plot of land, each side of which measures 1 kilometer (approximately 0.621 miles). It's a commonly used unit to measure land area, particularly in countries that use the metric system.