posted by Joe on .
how do I find a value of x that will make each proportion true??
12 = x
8 = 14
See previous post.
i still don't get it sorry
Cross multiply to find x.
Here's the first one; perhaps you can try the second one on your own.
12/16 = x/20
Take 12 * 20, which is 240. Take 16 * x, which is 16x. This is cross multiplying.
16x = 240
Divide both sides by 16 to solve for x.
You will find that x = 15
You can check by substituting 15 for x in your original problem.
12/16 = 15/20
This is a true statement, so you know the answer is correct.
I hope this is clearer.
Thanks for posting, MathGuru. Really good work.