A square millimeter (often abbreviated as mm²) is a unit of area in the International System of Units (SI). It represents a square with sides that each measure 1 millimeter (mm) in length.
One square millimeter is equal to 0.000001 square meters (m²) because there are 1,000 millimeters in a meter, and when you square that length, you get 0.001 square meters. Alternatively, you can express it as 1 square meter being equal to 1,000,000 square millimeters.
To visualize the size of a square millimeter, you can think of an extremely small square with sides that are each 1 millimeter long. It is a minuscule unit of area and is often used for measuring very tiny objects or areas, especially in scientific and engineering applications where precision is crucial.
The "acre (US survey)" is a unit of area used specifically in the United States for land surveying and legal property descriptions. It is different from the standard acre used in other parts of the world. The U.S. survey acre 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 acre (US survey) is equal to approximately 4,046.872609874252 square meters (m²) or about 0.40468726 hectares (ha).
This unit is used in various land-related applications, especially in the United States, where the U.S. survey acre is employed for legal and historical reasons in land surveys, property descriptions, and land records. It's important to be aware of the specific units being used when dealing with land measurements in the United States to avoid discrepancies or errors.