# Question #b8d21

Mar 15, 2017

Actually in this case you do not need to do any calculations.
Centigrade freezing point $\to {0}^{o} C$

Fahrenheit freezing point $\to + {32}^{o} F$

$33 F$ is above freezing and $- 15 C$ is below freezing

#### Explanation:

However; If you needed to do the calculations there are three values you need to remember. I will show you a trick about deciding how to use them

As above:

Freezing in Fahrenheit is ${32}^{0}$
Freezing in Centigrade is ${0}^{0}$

$\textcolor{red}{\text{So there is 32 degrees difference IN THE SCALES USED}}$

$\textcolor{red}{\text{The 'MAGIC NUMBERS ARE 5, 9 AND 32}}$

Fahrenheit scale numbers are greater so

$\textcolor{b l u e}{\text{How to handle the 5 and 9}}$

Make the numbers greater so multiply by $\frac{9}{5}$

Make the numbers less so multiply by $\frac{5}{9}$

$\textcolor{b l u e}{\text{How to handle the difference of freezing point}}$

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Let the Fahrenheit temperature be $x$
Then the Centigrade equivalent is: $\left(x - 32\right) \times \frac{5}{9}$
Let the Centigrade temperature be $x$
Then the Fahrenheit equivalent is $\left(x \times \frac{9}{5}\right) + 32$