Convert from pied de roi to cubit [Royal Egyptian]

Unit Definition (pied de roi)
The pied is a traditional French foot. Pieds of various lengths were used in France, but the one best remembered now is the royal foot (pied de roi), called the Paris foot in English and the foot (French measure) in Canadian law. The pied de roi equals about 32.48 centimeters or 12.79 inches; the official Canadian definition is 12.789 inches (32.484 06 centimeters). Today the word pied is sometimes used informally in France as a metric unit equal to 30 centimeters. In French Canada, pied is generally used to refer to the English foot.

Unit Definition (cubit [Royal Egyptian])
The Cubit is a historic unit of distance frequently mentioned in the Bible. The word comes from the Latin cubitum, "elbow," because the unit represents the length of a man's forearm from his elbow to the tip of his outstretched middle finger. This distance tends to be about 18 inches or roughly 45 centimeters. In ancient times, the cubit was usually defined to equal 24 digits or 6 palms. The Egyptian royal or "long" cubit, however, was equal to 28 digits or 7 palms. In the English system, the digit is conventionally identified as 3/4 inch; this makes the ordinary cubit exactly 18 inches (45.72 centimeters). The Roman cubit was shorter, about 44.4 centimeters (17.5 inches). The ordinary Egyptian cubit was just under 45 centimeters, and most authorities estimate the royal cubit at about 52.35 centimeters (20.61 inches).