Solving Proportions with Decimals

In this video, Mr. J explains how to solve proportions where the unknowns are decimals. The method involves cross multiplication to form a one-step equation, which is then solved for the unknown variable. Two examples are provided: the first demonstrates solving for x, and the second includes rounding a decimal result. The video emphasizes the importance of cross multiplication and provides guidance on handling decimals and rounding.

What is the main method used to solve proportions with decimal solutions?

• Addition

• Subtraction

• Cross Multiplication

• Division

Tags

CCSS.7.RP.A.2C

In the first example, what is the value of x when solving the proportion x to 20 equals 3 to 8?

• 5.5

• 6.5

• 8.5

• 7.5

Tags

CCSS.7.NS.A.2D

CCSS.8.NS.A.1

What is the result of dividing 60 by 8 in the first example?

• 7.75

• 7.5

• 8.0

• 7.25

Tags

CCSS.HSA.APR.D.7

What is the purpose of using a dot for multiplication in the examples?

• To make it look neat

• To avoid confusion with the variable x

• To follow mathematical conventions

• To simplify the equation

Tags

CCSS.7.RP.A.3

What should you focus on when cross multiplying to solve a proportion?

• The order of multiplication

• The side of the equal sign

• Multiplying diagonally

• The size of the numbers

Tags

CCSS.7.RP.A.2C

In the second example, what is the initial equation formed after cross multiplying 6 to x equals 32 to 15?

• 6x = 90

• 90 = 32x

• 15x = 32

• 32 = 6x

Tags

CCSS.8.NS.A.1

CCSS.7.NS.A.2D

What is the decimal representation of 90 divided by 32 in the second example?

• 2.8125

• 2.825

• 2.75

• 2.85

What is the approximate value of x in the second example after rounding to the hundredths place?

• 2.80

• 2.81

• 2.82

• 2.83

Tags

CCSS.7.RP.A.2C

Why might you need to round a decimal solution in a proportion?

• To make it a whole number

• To simplify calculations

• To handle long or repeating decimals

• To match the original numbers

Tags

CCSS.7.EE.B.3

What is the key takeaway from the video on solving proportions with decimal solutions?

• Proportions are always equal

• Decimal solutions require careful handling

• Cross multiplication is not necessary

• Always use whole numbers

Tags

CCSS.7.EE.B.3