Ok, so I'm in algebra 1 (7th grade) and I'm having some trouble understanding why solving basic proportions works. I understand that a proportion is two equal ratios. So when one of the numbers is a variable, I'm able to solve for the variable, but I don't understand why it works. So when you start to cross-multiply, my question is why do you multiply the numerator of one ratio by the denominator of the other? I mean, the two ratios are totally separate, except for the fact that they are equal. So, why do you multiply them as if they were the same ratio. Sorry if my question was confusing, I just need someone to explain why solving proportions works the way it does.