I'm from Texas, and I don't recall either of these: pie(Spanish for foot) and vara (Spanish for rod) The vara was a surveying term.

According to the related links, 1 pie = 0.925853018373 feet. and there are some discrepancies in the vara (it varied from place to place).

One site I found a vara = 33 1/3 inches, but another stated 33 1/2, but went on to say that 36 vara = 100 feet, which corresponds to the 33 1/3 value, so that should be it (for Texas anyway). With this measurement of 33 1/3 inches, 3 pies = 1 vara.