I am confused about problems that place the variable in the denominator position. Right now I'm doing a simple proportion problem.
$2/10/x=1/4$

I can not figure how too do this. I assume that I'm just missing something simple.

2. Originally Posted by bkbowser
I am confused about problems that place the variable in the denominator position. Right now I'm doing a simple proportion problem.
$2/10/x=1/4$

I can not figure how too do this. I assume that I'm just missing something simple.
When you divide by something, that's identical to multiply by it's inverse.

So for example $a / \bigg(\frac{b}{c}\bigg) = a \times \frac{c}{b}$

So $2 / \bigg( \frac{10}{x} \bigg)= 2 \times \frac{x}{10} = \frac{x}{5}$

3. So i can rewrite it as
$2*x/10=1/4$

Then multiply both sides by 10
$2*x=10/4$

then divide by 2?

$x=10/4/2$

4. Originally Posted by bkbowser
So i can rewrite it as
$2*x/10=1/4$

Then multiply both sides by 10
$2*x=10/4$

then divide by 2?

$x=10/4/2$

Yep.

5. Does that first step that I was missing have a name? This has been screwing with me for a few weeks. And I'd like to have as much information about it as i can, it helps me to remember.

6. Originally Posted by bkbowser
Does that first step that I was missing have a name? This has been screwing with me for a few weeks. And I'd like to have as much information about it as i can, it helps me to remember.
Hmm, if it does have a name, I don't know it!

Just remember that division = multiplication by the inverse.