A proportion is shown.

14/21 = x/24

What is the value of x?

To solve proportions, what you do is cross multiply. This is when you multiply the numerator of one fraction to the denominator of the other, both ways.

So basically, it would be 14 * 24 = 21x

And then you can just solve.

336 = 21x

/21 / 21

x = 16