The term "circular inch" is not a standard unit of measurement within the International System of Units (SI) or any widely recognized system of measurement. It's not commonly used in scientific or engineering contexts.
However, it's possible that the term "circular inch" may be used informally or in specialized industries to describe a measurement related to the circumference or area of a circle, particularly in contexts where precision matters. If you encounter this term, you would need to refer to the specific context or industry where it's being used to understand its meaning and how it is being applied.
The "square mile (US survey)" is a unit of area used in the United States primarily for land surveying and mapping purposes. It is different from the standard square mile, as 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 mile (US survey) is equal to approximately 3,097,600 square square meters (m²) or about 2.589988110336 square kilometers (km²).
This unit is used in various land-related applications, particularly in the United States, where the U.S. survey foot and the square mile (US survey) are still employed for legal and historical reasons in certain land surveys and property descriptions. It is important to be aware of the specific units being used when dealing with land measurements to avoid any discrepancies or errors.