|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
The foot (pl. feet; abbreviation: ft; symbol: ′, the prime symbol) is a unit of length in the imperial and US customary systems of measurement. Since 1959, both units have been defined by international agreement as equivalent to 0.3048 meters exactly. In both systems, the foot comprises 12 inches and three feet compose a yard.
The link (usually abbreviated as "l.", "li." or "lnk."), sometimes called a Gunter’s link, is a unit of length formerly used in many English-speaking countries. A link is exactly 66⁄100 of a foot, or exactly 7.92 inches or 20.1168 cm.