Solving Proportions: Key Concepts and Techniques

Charlie Kov, a math teacher, explains how to set up and solve proportions. He introduces the concept of proportional relationships, using an example involving dogs and people. The video demonstrates solving proportions through cross-multiplication and highlights the importance of simplifying proportions. The lesson concludes with a recap of the key points.

What does it mean when two things are proportional to each other?

• They increase at different rates.

• One increases while the other decreases.

• They increase at the same rate.

• They decrease at the same rate.

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CCSS.7.RP.A.2D

If the number of dogs is proportional to the number of people, and there are 4 dogs for 6 people, how many dogs are there for 9 people?

• 7 dogs

• 8 dogs

• 6 dogs

• 5 dogs

In the proportion 4 is to X as 6 is to 9, what is the value of X?

• 7

• 6

• 5

• 8

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CCSS.7.RP.A.2B

What is the first step in solving the proportion 4/X = 6/9?

• Subtract 6 from 9

• Divide 6 by 9

• Cross-multiply 4 and 9

• Add 4 and 6

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CCSS.7.RP.A.2B

After cross-multiplying 4 and 9, what is the next step to find X in the proportion 4/X = 6/9?

• Subtract 6 from 36

• Add 36 and 6

• Divide 36 by 6

• Multiply 36 by 6

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CCSS.7.RP.A.3

How can the proportion 6 to 9 be simplified?

• 4 to 5

• 1 to 2

• 3 to 4

• 2 to 3

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CCSS.6.RP.A.1

CCSS.6.RP.A.2

What is the simplified form of the proportion 4 to 6?

• 1 to 2

• 2 to 3

• 3 to 4

• 4 to 5

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CCSS.6.RP.A.3A