Cross Multiply, then Divide

Front

What is cross multiplication?

Back

Cross multiplication is a method used to solve proportions by multiplying the numerator of one fraction by the denominator of the other fraction and vice versa.

Front

How do you solve for X in a proportion?

Back

To solve for X in a proportion, cross multiply the two fractions and then isolate X by dividing.

Front

If 3/4 = X/12, what is X?

Back

X = 9 (Cross multiply: 3 * 12 = 4 * X, so 36 = 4X, thus X = 9).

Front

What is the first step in solving a proportion?

Back

The first step is to cross multiply the two fractions.

Front

If Nathan packs 39 boxes in 3 hours, how many boxes does he pack per hour?

Back

He packs 13 boxes per hour (39 boxes ÷ 3 hours = 13 boxes/hour).

Front

If Nathan works an 8-hour shift, how many boxes can he pack?

Back

He can pack 104 boxes (13 boxes/hour * 8 hours = 104 boxes).

Front

What does it mean to isolate a variable?

Back

To isolate a variable means to get the variable alone on one side of the equation.

Front

In the equation 2X = 14, what is X?

Back

X = 7 (Divide both sides by 2).

Front

What is the cross product of 5/6 and X/12?

Back

The cross product is 5 * 12 = 60, so 60 = 6X.

Front

If 6X = 60, what is X?

Back

X = 10 (Divide both sides by 6).