**Example 1: Solve the proportion for ***x*.

$\frac{3}{8}=\frac{12}{x}$

- Find the scale factor. In this example the scale factor is 4 (3 × 4 = 12).
- Multiply by the scale factor.

$\frac{3\left(4\right)}{8\left(4\right)}=\frac{12}{x}$

- Since
*x* is in the denominator, find the denominator. *x* = 8(4) = 32

* x* = 32

**Example 2: Solve the proportion for x.**

$\frac{2}{7}=\frac{x}{21}$

- Find the scale factor. In this example the scale factor is 3 (7 × 3 = 21).
- Multiply by the scale factor.

$\frac{2\left(3\right)}{7\left(3\right)}=\frac{x}{21}$

- Since
*x* is in the numerator, find the numerator. *x* = 2(3) = 6

* x* = 6

**Pause and Reflect**

Once you have the proportion written, how could you solve the proportion?