Convert from degree Fahrenheit to degree Reaumur

Unit Definition (degree Fahrenheit)
Degrees Fahrenheit is a common unit of temperature still widely used today. The unit was defined by the German physicist Daniel Fahrenheit. Fahrenheit set 0° at the coldest temperature he could conveniently achieve using an ice and salt mixture, and it is said he intended to set 96°F as the temperature of the human body. On his scale, the freezing point of water (at 1atm.) turned out to be ~32°F and the boiling point ~212°F. Eventually the scale was precisely defined by these two temperatures.

Unit Definition (degree Reaumur)
The degree Réaumur is a unit of temperature formerly used in continental Europe. The Réaumur temperature scale is named for the French scientist René-Antoine Ferchault de Réaumur (1683-1757). It is similar to the Celsius scale in having its zero point at the freezing temperature of water, but the interval between the freezing and boiling temperatures of water equals 80 °r instead of 100 °C. Therefore, 1 °r equals 1.25 °C or 2.25 °F.