Convert from rai to morgen [Germany]

Unit Definition (rai)
The rai is a traditional unit of land area in Thailand. The rai is now considered to equal exactly 1600 square meters, which is 0.16 hectare or approximately 0.3954 acre. The rai is divided into 4 ngan. The unit is called the hai in northern Thailand and the lai in Laos. The word means "field," that is, an upland field rather than a rice paddy.

Unit Definition (morgen [Germany])
The morgen is a traditional unit of land area in Northern Europe. "Morgen" means "morning," and most likely the unit arose as the area a yoke of oxen could plow in one morning. The Dutch morgen, also used in Dutch colonies including old New York, equals about 2.10 acres or 0.850 hectare. In South Africa, this unit was defined to equal 10 246 square yards, which is 2.1169 acres or 0.8567 hectare. In Scandinavia and northern Germany, the morgen is a smaller unit equal to about 0.63 acre or 0.25 hectare (2500 square meters). The Prussian morgen, standardized at 2553.22 square meters, was in common use during the nineteenth century. In Austria and southern Germany, the morgen was often the same as a joch, typically defined to be 0.5755 hectare or about 1.422 acres.