Convert from cuerda to tunnland

Unit Definition (cuerda)
The Cuerda is a traditional unit of land area in Puerto Rico. The cuerda is equal to about 3930 square meters, 4700 square yards, 0.393 hectare, or 0.971 acre. Because the cuerda and the acre are so close to being equal, they are often treated informally as being equal. Mainlanders sometimes call the unit the "Spanish acre."

Unit Definition (tunnland)
The tunnland is a traditional unit of land area in Sweden. The tunnland is equal to 56 000 square Stockholm feet (kvadratfot); this is equivalent to 4936.4 square meters, 0.493 64 hectare, or about 1.220 English acre. The tunnland was divided into 32 kappland. Like the Danish tønde land (see above), this unit originated as the area that could be planted with one tunn (barrel) of seed.