Cross Multiplying Examples

This page is to illustrate the concept of cross-multiplying. See the examples below to study the pattern.

Example 1

Find the value of x in the following proportion:

Solution

1. First, multiply the two numbers that are diagonally across the equals sign from one another (8 and 36 as shown below):

So far, we have 8 x 36 = 288.

2. Now divide your result from step 1 by the remaining number (96). 288 ÷ 96 = 3

Our solution to this problem is x = 3.

Example 2

Find the value of y in the following proportion:

Solution

Don't worry that the variable in this example is found in the denominator. Cross-multiply and divide works no matter where the variable is located!

1. Again, your first step is to multiply the two numbers that are found diagonally across the equals sign from one another. (14 and 99 in this example, as shown below):

That gives us 14 x 99 = 1386

2. Now it's time for the divide part! Divide your result from step 1 by the leftover number. 1386 ÷ 126 = 11

The value of y in this proportion is 11.

Now you can try some sample questions, or you can head back to the proportions main page.