First, multiply the Celsius temperature by 9. In this case, multiply 39 by 9 for a product of 351.
Once you have an answer from multiplying, divide it by 5. In this conversion, divide 351 by 5. The answer is 70.2.
Finally, add 32 to the quotient. For this example, add 70.2 and 32 for a sum of 102.2. 39 C converts to 102.2 F.
Check your answer by using an online conversion calculator. Enter your original Celsius temperature into the calculator to see if your answer was correct. This is a simple way to ensure your performed your conversion correctly.
If you don't have paper and pencil handy to perform these calculations, or if you cannot access an online conversion tool, try looking at a thermometer. Many thermometers have both Celsius and Fahrenheit listed on each side. Find the temperature on the Celsius scale, and look across the thermometer to the Fahrenheit scale to find the correct temperature.