Convert from stadium to ri [Japan]

Unit Definition (stadium)
The stadium is a historic unit of distance originating in ancient Greece. Greek athletic fields were all of roughly the same size, and the stadion, equal to 600 podes (feet), was the traditional length of the field. Archaeological measurements show that the stadion was a little more than 200 yards or a little less than 200 meters. The stadion at Olympia, where the original Olympic Games were held, measures 630.8 feet or 192.3 meters; at Athens the stadion was 606.9 feet or 185.0 meters. Stadium is the Latin spelling; in the Roman world the stadium was equal to 625 Roman feet (pes) or 1/8 Roman mile. This is equivalent to 606.95 feet, 202.32 yards, or 185.00 meters. The plural is stadia.

Unit Definition (ri [Japan])
The ri is a traditional Japanese unit of distance, sometimes called the Japanese league because it is of similar length to the European league. The ri equals 2160 ken or 12 960 shaku (the shaku being the Japanese equivalent of the foot). This is about 3927 meters or 2.44 statute miles.