Convert from ridge to bicron

Unit Definition (ridge)
The ridge is a traditional Welsh unit of distance equal to 3 leaps or 20 feet 3 inches (6.1722 meters).

Unit Definition (bicron)
The Bicron is an obsolete metric unit of distance, which was defined as 10e-12 meter or 10e-6 micron. This distance is now called a picometer or picometre (pm). The name is a reference to the double prefix "micro-micron".