What is the formula to convert Fahrenheit to Celsius?

The formula to convert Fahrenheit to Celsius is indeed (℉ - 32) / 1.8. This formula stems from the relationship between the two temperature scales, where the freezing point of water is 32°F and 0°C, while the boiling point is 212°F and 100°C, respectively.

To derive the formula, you start with the two fixed points on both temperature scales and the fact that the degrees Fahrenheit and degrees Celsius differ in size; specifically, there are 180 degrees between the freezing and boiling points in Fahrenheit and 100 degrees in Celsius. The conversion requires subtracting 32 from the Fahrenheit temperature to account for the offset, and then dividing by 1.8 to adjust for the difference in degree size. This conversion enables accurate representation of the same temperature in Celsius, thereby ensuring the correct communication of thermal readings between the two systems.

The alternative choices do not appropriately represent the conversion process, either by adding rather than subtracting the offset or misapplying the multiplicative factor.