Convert from military pace [double time] to legua [Spanish, pre-1568]

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).

Unit Definition (legua [Spanish, pre-1568])
Unit of area used in the southwest US, equal to 25 labors, or 4428 acres (Texas), or 4439 acres (California). Also, a unit of length-- approximately three miles.