Convert from line to military pace [double time]

Unit Definition (line)
The line is a traditional unit of distance equal to 1/12 inch (about 2.1167 millimeters). For measuring the thickness of buttons, there is also a smaller line equal to 1/40 inch (0.635 millimeter). The line is called the ligne in French, the linea in Spanish, the linie in German, and the liniya in Russian.

Unit Definition (military pace [double time])
The length of a single step in marching (taken to be 30 inches for quick time or 36 inches for double time).