Solving Proportions with Variables

In this video, Mr. J explains how to solve proportions using cross multiplication. Proportions are two equivalent ratios, and the video demonstrates solving for missing variables in these proportions through four examples. Each example involves setting up a cross multiplication equation and isolating the variable to find its value. The video concludes with a summary of the method and encourages viewers to practice the technique.

What is the purpose of cross multiplication in solving proportions?

• To find the value of the unknown variable

• To subtract the known values from each other

• To multiply numbers across the proportion

• To add values on both sides of the equation

What is the first step in solving proportions using cross multiplication?

• Divide both sides by the variable

• Add the values on both sides

• Draw arrows to represent cross multiplication

• Isolate the variable

What does cross multiplication help to eliminate in solving proportions?

• The fractions in the equation

• The need for addition

• The variable from the equation

• The need for subtraction

In the first example, what is the value of 'N' when 4/10 equals N/25?

• 5

• 20

• 10

• 15

How do you isolate the variable in a proportion equation?

• By multiplying both sides by the variable

• By dividing both sides by the multiplier of the variable

• By subtracting the multiplier

• By adding both sides

How do you find the value of the variable in a proportion?

• By dividing the known value by the variable

• By subtracting the known value from the variable

• By adding the values on both sides

• By cross multiplication and isolating the variable

Why is it important to isolate the variable when solving proportions?

• To simplify the equation

• To prepare the equation for addition

• To find the value of the variable

• To eliminate the denominator

What is the value of 'X' when 8/20 equals X/15?

• 6

• 7

• 5

• 4

In the third example, what does 'M' equal when 9/12 equals M/6?

• 7

• 9

• 6

• 8

What is the result of 'W' in the equation 10/W equals 5/9?

• 15

• 16

• 17

• 18