What is the name of the 19th-century Spanish unit of measurement used in Texas, where to convert to feet, you divide by 0.36?

The correct answer is "Varas." In the context of 19th-century land measurement in Texas, the vara was a customary unit of length. Specifically, the vara is equivalent to approximately 33 inches or 2.75 feet. The conversion factor mentioned — dividing by 0.36 — indicates that to convert varas into feet, the relationship is approximately 1 vara equals 0.36 feet. This historical unit is significant in Texas land surveys and reflects the state's colonial Spanish heritage, influencing property descriptions and boundaries.

The other options, while they may have historical relevance in surveying or land measurement, do not align with the specific conversion factor given in the question. Leagues represent a much larger measurement (typically about three miles), arpents are primarily associated with land area (especially in French context), and estates refer to a type of property or land ownership rather than a unit of measurement. Therefore, varas is the correct unit related to the question's specifics.