Dimensional analysis for obtaining a quantity in units of Celsius from units of Fahrenheit; one could have started with the equivalence between 100 °C and 212 °F, though this would yield the same formula at the end. Hence, to convert the numerical quantity value of a temperature "T"[F] in degrees Fahrenheit to a numerical quantity value "T"[C] in degrees Celsius, this formula may be used: To convert "T"[C] in degrees Celsius to "T"[F] in degrees Fahrenheit, this formula may be used: Dimensional analysis is most often used in physics and chemistry – and in the mathematics thereof – but finds some applications
Celsius called "centigrade", from the Latin "centum", which means 100, and "gradus", which means steps. From 1743 to 1954, the Celsius scale was based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure. Prior to 1743, the scale was also based on the boiling and melting points of water, but the values were reversed (i.e. the boiling point was at 0 degrees and the melting point was at 100 degrees). The 1743 scale reversal was proposed by Jean-Pierre Christin. By international agreement, since 1954 the unit and the