# How do you solve 12/7=36/m?

Mar 19, 2017

$\textcolor{g r e e n}{m = 21}$

#### Explanation:

There are several ways to solve this, but since it was asked under "Rational Equations Using Proportions" let's approach it that way.

Notice that $36$ is $12 \times 3$.

If we multiply the Left Side by $\frac{3}{3}$ (equivalent to multiplying by $1$)
we get:
$\textcolor{w h i t e}{\text{XXX}} \frac{12}{7} \times \frac{3}{3} = \frac{36}{21}$

and our original equation
$\textcolor{w h i t e}{\text{XXX")12/7=36/mcolor(white)("XX}}$becomes$\textcolor{w h i t e}{\text{XX}} \frac{36}{21} = \frac{36}{m}$
with the implication that
$\textcolor{w h i t e}{\text{XXX}} m = 21$