Solve for Proportions using Cross Multiplication

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

What does cross multiplication involve?

Back

Cross multiplication involves multiplying the numerator of one ratio by the denominator of the other ratio.

Front

If a/b = c/d, what is the cross multiplication equation?

Back

a * d = b * c.

Front

Solve for x: 2/x = 4/8

Back

x = 4.

Front

Solve for b: 3/b = 6/12

Back

b = 6.

Front

What is the first step in solving a proportion using cross multiplication?

Back

Identify the two ratios and set them equal to each other.

Front

If 5/x = 10/20, what is x?

Back

x = 10.

Front

What is the solution to the proportion 4/5 = x/15?

Back

x = 12.

Front

How do you check if your solution for a proportion is correct?

Back

Substitute the value back into the original proportion to see if both sides are equal.

Front

Solve for x: 7/x = 14/28

Back

x = 14.