This Cross Multiplication Calculator is used to solve for x with fractions. This is also known as proportions and what we need to do is remove fractions from an equation by multiplying each side by the common multiple of the denominators of the fractions of both sides. No matter which of the four values is unknown, after we cross multiply and divide, we can definitely get our answer. We will show we how to solve it easily below.

Easy-To-Remember Formulas

How to find x using cross multiplication?

Example 1:

1.) Cross Multiply:

9 * -2 = 5.8 * C

2.) Divide each side by -5.8:

C = (-2 * 9) / 5.8

3.) Reduce:

C = -3.103

4.) Solve for x:

-3.103 = 7x

5.) Divide each side by 7:

-3.103/7 = x

x = -0.44328571

Example 2:

1.) Cross Multiply:

6 * 3 = 8 * B

2.) Divide each side by 8:

B = (3 * 6) / 8

3.) Reduce:

B = 2.25

x = 2.25

Example 3:

1.) Multiply fraction by x:

(2/5) * (x/1)

(2x/5)

(2x/5) = (63/7)

So now we solve for A to find x

2.) Cross Multiply:

7 * A = 63 * 5

3.) Divide each side by 7:

A = (63 * 5) / 7

4.) Reduce:

A = 45

4.) Solve for x:

45 = 2x

5.) Divide each side by 2:

45/2 = x

x = 22.5