Description: In this example we have a formula for converting Celsius temperature to Fahrenheit. Let's substitute the variable with a value (Celsius temp) to get the degrees in Fahrenheit. Express 25 degrees Celsius as a temperature in degrees Fahrenheit using the formula Fahrenheit, or F, is equal to 9/5 times the Celsius degrees plus 32. So we could put that in for C here, and we'll get the temperature in Fahrenheit degrees. Or it's equal to 45 plus 32 is 77, so this is 77 degrees Fahrenheit.*Teacher Advisor is 100% free.