An acre (ac) is a unit of area commonly used in the United States and some other countries, especially for measuring land area, particularly in the context of real estate and agriculture.
One acre is equivalent to 43,560 square feet or 4,840 square yards. In terms of square meters, it is approximately 4,046.86 square meters.
To provide some perspective, an acre is roughly the size of a football field, excluding the end zones. It is a common unit for describing land area in rural and suburban areas, as well as for determining the size of plots of land, farms, and other land parcels.
A square perch, often referred to as a "square pole" or simply "perch," is an obsolete unit of land area measurement. It was historically used in some English-speaking countries, including the United States and the United Kingdom, for land surveying and property descriptions.
One square perch is equivalent to one square rod or one square pole. In terms of modern measurements, one square perch is approximately equal to 25.29285264 square meters (m²) or 0.00625 acres.
Like other obsolete units of land area measurement, the square perch has largely been replaced by more standardized systems of measurement, such as square meters and square feet, in modern times. It is rarely encountered in contemporary land transactions or legal documents.