Convert from hair's breadth to pie [Spanish]

Unit Definition (hair's breadth)
The hair's breadth is a common informal unit of distance. Human hairs vary considerably in width, depending on age, color, genetics, and other factors. An average hair is approximately 70 to 100 micrometers (µm) in diameter, so, as a rough standard, a hair's breadth is 100 µm or 0.1 millimeter (mm).

Unit Definition (pie [Spanish])
The pie is a traditional foot of Spain. The pie equals 1/3 vara or 12 pulgadas. The pie used in Spain is about 27.86 centimeters or 10.97 inches, but in Spanish Latin America the pie is generally longer.