Help! Simple math but stuck anyways... :-(

Impossible to prove for it always to be true because if a=2 b=4 c=4 d=8

so a/b=c/d would be 2/4=4/8 so impossible

how can I prove, mathamaticlly, that because a/b=c/d, therefore a=c and b=d?

You cannot prove it because it isn't true :)

eg

\(\frac{2}{3}=\frac{10}{15}\)

but 2 not equal 10

and

3 not equal 15

This isn't generally true.....for instance

4 / 5   = 8 / 10

But, 4 doesn't equal 8  and 5 doesn't equal 10, either.

One thing that IS true is cross- product equality.....that is.....

4 * 10   = 5 * 8   →  [ad   = bc]

Thanks Chris :)