Understanding Proportions

This video tutorial covers the concept of proportions, explaining how to determine if two pairs of numbers form a proportion and how to solve proportions. It introduces the idea of cross products, which are used to verify if two ratios are equal. The video provides examples to illustrate the process of checking proportions and solving for missing values in a proportion. It also includes more complex examples to deepen understanding.

What is the key concept of a proportion?

• Two numbers are equal.

• Two ratios are equal.

• Two sums are equal.

• Two products are equal.

If two ratios form a proportion, what must be true about their cross products?

• They must be different.

• They must be zero.

• They must be equal.

• They must be negative.

In the example with ratios 24:36 and 1.8:2.7, what is the result of the cross products?

• 48.00

• 72.00

• 36.00

• 64.88

What is the result of the cross products for the ratios 10:8 and 14:11?

• 110 and 112

• 112 and 110

• 120 and 100

• 100 and 120

When solving a proportion with a missing number, what is the first step?

• Add the numbers.

• Subtract the numbers.

• Find the cross products.

• Divide the numbers.

In the example where 2x equals 40, what is the value of x?

• 20

• 15

• 25

• 10

What is the value of n when 8n equals 43.2?

• 7.2

• 4.5

• 5.4

• 6.4

In the complex example, what is the value of y when 5y equals 2?

• 3/5

• 2/5

• 4/5

• 1/5

What is the result of one-third times six in the complex example?

• 4

• 3

• 2

• 1

What is the purpose of cross multiplying in solving proportions?

• To subtract the numbers.

• To add the numbers.

• To find the sum.

• To form an equation.