Convert from vara [South America] to fermi

Unit Definition (vara [South America])
Vara is an old Spanish and Portuguese unit of length. Varas are a surveying unit that appears in many deeds in the southern United States, and varas were also used in many parts of Latin America. It varied in size at various times and places; the Spanish unit was set at about 835.9 mm in 1801. At some time value of 33 in (838 mm) was adopted in California, and 33 1/3 inches (847 mm) in Texas.

Unit Definition (fermi)
The Fermi was a metric unit of distance formerly used in atomic physics. One Fermi equals 10e-15 meter, or 1 femtometer. The unit was named after Enrico Fermi (1901-1954), the Italian-American physicist who built the first nuclear reactor.