For converting Celsius (°C) to Fahrenheit (°F), use $F = C\times _____ + 32$.

### Why this is right The Celsius-to-Fahrenheit relationship multiplies the Celsius value by $9/5$ and then adds 32. The factor changes the size of the temperature interval, and the addition shifts the zero point. ### The concept The reverse conversion uses a different order and factor: Fahrenheit to Celsius subtracts 32 and multiplies by $5/9$. These formulas are inverses, so using the wrong direction produces an incorrect value. ### Worked numbers - **Formula**: $F=C\times9/5+32$, where $C$ is Celsius and $F$ is Fahrenheit. ### Terms - **Celsius (°C)**: a temperature scale. - **Fahrenheit (°F)**: a temperature scale. ### Remember Celsius to Fahrenheit means multiply by $9/5$, then add 32.