Question

How do you use cross products to solve `30/6=b/7`?

Answer 1

`b = 35`

Explanation:

eliminate the denominators so that you can get an idea as to what b will become

`30/6 = b/7` cross multiply the denominators by the other numerators

`30(7) = b(6)`

`210 = 6b` divide both sides by 6 to isolate b

`b = 35`

a faster way to do this is by seeing that `30/6` equals `5/1`. take that `5` and multiply it by `7` to get `35`

Answer 2

`b=35`

Explanation:

`"given equal fractions "a/b=c/d`

`"then "ad=bclarrcolor(blue)"cross product"`

`"using this method to solve the equation"`

`rArr6b=(30xx7)`

`rArrb=(30xx7)/6=35`