Algebra math question on proportions?

Question

find the cross products

68/168 X/180

please explain because im confused on how to do this

Answer 1

It's just asking you to solve for x... like this, right?

  68 *  x  

168    180

all you have to do is multiply diagonally, top left & bottom right, bottom left & top right, and set each product equal to the other, like this:

168x=68*180

divide both sides by 168, and you get your answer

x=72.86