A ** proportion** is an equation that compares fractions that are equal. The proportion can be divided into 4 parts, the numerator and denominator of the two fractions.

The numerator of the first fraction and the denominator of the second fraction are called the ** extremes** (shown in

The denominator of the first fraction and the numerator of the second fraction are called the

**(shown in**

__means__Solve for x:

1 x - = -2 6

__Cross Product:__

In order to solve for x, we use the algebraic property that the product of the extremes is equal to the product of the means. This is called the **cross product**.

Let’s try to solve the problem above.

1 *6 =2 *x 6 =2x 3 =x

If we plug in x = 3, we see that the fractions are equal.

1 3 - = -2 6

Using what we know about cross-product, let’s try another problem!

Solve for x:

2 8 - = -5 x

Remember that the extremes are in

2 *x =8 *5 2x =40 x =20

We plug in x = 20 and notice that the fractions are equal.

2 8 - = --5 20