Cross Multiplication and Proportions

This video tutorial explains how to solve proportions using cross multiplication, also known as the cross product method. The instructor provides multiple examples, highlighting common mistakes and guiding viewers through the correct steps. The video also mentions alternative methods for solving proportions, such as the giant one and undoing division, with links provided for further exploration. Viewers are encouraged to pause and practice the problems independently to reinforce learning.

What is another name for the cross product method?

• Cross multiplication

• Cross subtraction

• Cross addition

• Cross division

Which of the following is NOT a method to solve proportions?

• Cross addition

• Cross multiplication

• Giant one

• Undoing division

In cross multiplication, which parts of the fractions are multiplied together?

• Numerator of the first and denominator of the second

• Denominator of the first and numerator of the second

• Numerator of both fractions

• Denominator of both fractions

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

• Add the numerators

• Multiply the numerators

• Subtract the denominators

• Cross multiply the numerator of the first fraction with the denominator of the second

What mistake should be avoided when using cross multiplication?

• Multiplying the numerators together

• Cross multiplying the denominator of the first with the numerator of the second

• Multiplying the denominators together

• Cross multiplying the numerator of the first with the denominator of the second

In the first example, what is the value of x when 3x = 60?

• 25

• 30

• 15

• 20

What operation is performed after cross multiplication to solve for x?

• Multiplication

• Division

• Subtraction

• Addition

In the second example, what is the result of 63x = 126?

• x = 4

• x = 3

• x = 2

• x = 1

What is the correct pairing for cross multiplication in the second example?

• 63 and x, 7 and 18

• 63 and 18, x and 7

• 63 and 7, x and 18

• 63 and 18, 7 and x

In the third example, what is the value of x when 15x = 90?

• x = 5

• x = 4

• x = 7

• x = 6