A square rod is a unit of area measurement that is now considered obsolete and not commonly used in modern times. It was historically used in some English-speaking countries, including the United States and the United Kingdom, as part of the older system of land measurement.
One square rod is equal to an area of 1/160th of an acre or 1/4,840th of a square yard. In terms of square meters, one square rod is approximately equal to 25.29285264 square meters (m²).
The square rod was often used in land surveys and property descriptions in the past, but it has been largely replaced by more standardized systems of measurement. In modern times, square meters and square feet are the more commonly used units for measuring land area.
A square decameter (often abbreviated as dam²) is a unit of area in the International System of Units (SI). It represents a square with sides that each measure 10 meters (1,000 centimeters) in length.
One square decameter is equal to 100 square meters (m²) because each side of the square is 10 meters long, and when you square that length, you get 100 square meters.
Square decameters are not as commonly used as some other units of area, but they can be used to describe moderate-sized land areas, and they are a part of the metric system for measuring area.