what is this method?

[greghendricks]

if I want to find a in the equation I would take term a and divorce it by term but and multiply that by term c to get term d, what is the name of this method?

 

[Steven G]

You have 4 factors, A, B, C and D. You can move any factor from the top to the bottom or the bottom to the top as long as you cross the equal sign. So in r/s = t/u you can move u and s to get ru = st or move r and u to get u/s=t/r or if you move s you get r=st/u.

The method in my opinion is called multiplication

 

[Dr.Peterson]

if I want to find a in the equation I would take term a and divorce it by term but and multiply that by term c to get term d, what is the name of this method?

This makes no sense. If A is 15.84, why would you need to find it? What does "divorce" mean? Why didn't you use B? If you want to "get" A, why do you end up "getting" D?

The closest I can come to making sense is the method of "cross-multiplication", where you multiply "opposite" numbers to change [MATH]\frac{C}{B} = \frac{D}{A}[/MATH] to [MATH]AC = BD[/MATH]. This is just a shortcut for multiplying both sides of the equation by [MATH]AB[/MATH]. Long ago this was called "the rule of three", and you would be taught simply to multiply AC and divide by B to get x (D). But both of these ways to express it rely on rote memory rather than understanding of algebra.