Which formula is used to convert Celsius to Fahrenheit?

The formula used to convert Celsius to Fahrenheit is F = 9/5C + 32. This means that to convert a temperature from Celsius (C) to Fahrenheit (F), you multiply the Celsius temperature by 9/5 (or 1.8) and then add 32 to the result. This conversion is based on the relationship between the two temperature scales, where water freezes at 0 degrees Celsius and 32 degrees Fahrenheit, and boils at 100 degrees Celsius and 212 degrees Fahrenheit.

In contrast, the first option you selected, C = 5/9(F - 32), actually describes how to convert Fahrenheit back to Celsius rather than the other way around. The correct conversion formula allows for a straightforward calculation of Fahrenheit temperatures based on the Celsius values, which is fundamental in scientific contexts where temperature measurement is often given in either of the two scales.