# Using Cross Products To See If Each Pair Of Ratios

## Introduction

When we talk about ratios, we are talking about the relationship between two numbers. A ratio is simply a way of comparing two values. For example, if we say that the ratio of apples to oranges is 2:1, we mean that for every two apples, there is one orange. Ratios are essential in many areas of mathematics, including geometry, algebra, and statistics.

### What are Cross Products?

Cross products are a method used to compare two ratios. When we have two ratios, we can use cross products to determine if they are equivalent. The cross product of two ratios is simply the product of the numerator of one ratio and the denominator of the other. For example, if we have the ratios 2:3 and 4:6, we can find the cross product by multiplying 2 by 6 and 3 by 4. The cross products are 12 and 12, respectively.

### Using Cross Products to Compare Ratios

Once we have the cross products, we can compare them to see if the two ratios are equivalent. If the cross products are equal, then the two ratios are equivalent. If the cross products are not equal, then the two ratios are not equivalent. In the example above, the cross products are equal (12 and 12), so we can say that the ratios 2:3 and 4:6 are equivalent.

### Real-Life Applications of Cross Products

Cross products are used in many real-life situations. For example, if you go to the grocery store and see that apples are being sold for \$2.50 per pound and oranges are being sold for \$1.50 per pound, you can use cross products to determine which fruit is the better deal. The ratio of the price of apples to oranges is 2.5:1.5. We can find the cross product by multiplying 2.5 by 1 and 1.5 by 1. The cross products are 2.5 and 1.5, respectively. Since the cross product for apples is larger than the cross product for oranges, we can say that apples are more expensive than oranges.

## How to Use Cross Products to Compare Ratios

Now that we know what cross products are and how they are used, let’s look at how to use them to compare ratios in more detail.

### Step 1: Write the Ratios

The first step is to write down the ratios that you want to compare. For example, if we want to compare the ratios 2:3 and 4:6, we write them as follows: 2:3 and 4:6

### Step 2: Find the Cross Products

The next step is to find the cross products. To do this, we multiply the numerator of one ratio by the denominator of the other ratio. In our example, we multiply 2 by 6 and 3 by 4, as follows: 2 x 6 = 12 3 x 4 = 12

### Step 3: Compare the Cross Products

After we have found the cross products, we compare them to see if they are equal. If they are equal, the ratios are equivalent. If they are not equal, the ratios are not equivalent. In our example, the cross products are equal, so we can say that the ratios 2:3 and 4:6 are equivalent.

### Step 4: Simplify the Ratios

If the ratios are equivalent, we can simplify them by dividing both the numerator and denominator by the same number. For example, if we have the ratios 2:4 and 4:8, we can simplify them by dividing both by 2, as follows: 2:4 = 1:2 4:8 = 1:2

## Conclusion

Cross products are a powerful tool for comparing ratios. They allow us to determine if two ratios are equivalent quickly and easily. By following the steps outlined above, you can use cross products to compare ratios in any situation. Whether you’re comparing prices at the grocery store or solving math problems in the classroom, cross products are an essential tool for any math student or professional.