# What is 19°F in celsius?

##### 1 Answer
Apr 9, 2016

${19}^{o} F$ is equal to $- {7.2}^{o} C$.

#### Explanation:

In order to determine how many degrees 19 Fahrenheit is in Celsius we need to understand that there is an equation that we must use. To convert a temperature in Fahrenheit to Celsius that equation looks like this:

$\left({F}^{o} - 32\right) \cdot \frac{5}{9} = {C}^{o}$

${F}^{o}$ represents the temperature in Fahrenheit, which we just so happen to be given. While the ${C}^{o}$ represents the temperature in Celsius which we are asked to find. This means that we can substitute the ${F}^{o}$ for ${19}^{o} F$, the equation would then look like this:

$\left({19}^{o} F - 32\right) \cdot \frac{5}{9} = {C}^{o}$

Now we can solve for ${C}^{o}$ by using order of operations (PEMDAS).

-------------------------------

Here's a quick refresher on PEMDAS:

First (P): we do anything in parentheses

Second (E): we do anything raised to a power, exponents

Third (M): we do any multiplication

Fourth (D): we do any division

Fifth (A): we do any addition

Sixth (S): we do any subtraction

-------------------------------

Okay now that's out of the way let's solve!

$\left({19}^{o} F - 32\right) \cdot \frac{5}{9} = {C}^{o}$

$= - {13}^{o} F \cdot \frac{5}{9}$

Okay this might look intimidating but, its not I promise.

$= - {13}^{o} F \cdot \frac{5}{9}$

Is the same as this:

$- 13 \cdot \frac{5}{9}$

You could cheat by plugging this into a calculator but lets take a look at $\frac{5}{9}$:

$\frac{1}{9} = 0.1111$ those 1's actually go on repeating like that forever

Now,

$\frac{2}{9} = 0.2222$ with that same repeating trend

In fact this holds true for any number less than 9 that is over 9 (all numbers up to $\frac{8}{9} = 0.8888$. This means that:

$\frac{5}{9} = 0.5555$

For all intents and purposes we can round this to 0.556. Now we can multiply -13 by 0.556, this will give us the number of degrees Celsius:

$- 13 \cdot \left(0.556\right) = - {7.228}^{o} C$

We can round to get:

${19}^{o} F = - {7.2}^{o} C$

-------------------------------

In order to go from Celsius to Fahrenheit we can use this equation:

${C}^{o} \cdot \left(\frac{9}{5}\right) + 32 = {F}^{o}$

Instead of plugging in Fahrenheit we would plug in Celsius. For example: "What is -7.2^oC in Fahrenheit?"

I hope this helps!