Convert 21.4 °C into °F.

Step 1: Determine Which Formula to Use
Since we are given Celsius and are solving for Fahrenheit we will use the following formula:
(°C × 1.8) + 32 = °F
This formula shows that we got degrees Celsius and we are solving for degrees Fahrenheit.
Step 2: Substitute In Our Temperature
We are going to use the formula from Step 1, but insert the temperature we were given from our problem, in this case, 21.4 °C.
(21.4 °C × 1.8) + 32 = °F
Step 3: Solve Using Order of Operations
In going through PEMDAS, the order of operations, we first do what happens within the parentheses which is:
(21.4 °C × 1.8)
So this is what happens:
(21.4 °C × 1.8) + 32 = °F
Becomes:
38.52 + 32 = °F
We could drop the parentheses since we completed whatever was inside of them.
Now we can solve the problem.
38.52 + 32 = °F
Which becomes:
70.52 = °F
70.52 °F