7.rp.2 and 6.RP.3c Proportions and Percents

Proportions and Throwback to Percents

By Kara Robinson

Match

Warm-Up: Match the following

• Constant of Proportionality

• Independent variable

• dependent variable

• origin

• Equivalent

k

x

y

(0,0)

equal

• k

• x

• y

• (0,0)

• equal

7.RP.

• 2a Decide whether two quantities are in a proportional relationship

• 2b Identify the constant of proportionality

• 2c Represent proportional relationships by equations

• 2d Explain what a point (x,y) on the graph of a proportional relationship means in terms of the situation

Multiple Choice

Kolby can do 52 push-ups in 2 minutes. His friend Jared can do 130 push-ups in 5 minutes. Do these rates form a proportion?

• yes

• no

Decide whether two quantities are in a proportional relationship

Fill in the Blanks

2b Identify the constant of proportionality

​We know the CoP is 200 because when x = 1, y = 200

Multiple Choice

Selena and Dylan studied the data in the table. They each wrote an equation to represent the relationship between the number of students and the number of pizzas ordered. Who is correct?

• Selena

• Dylan

• Both Selena and Dylan

• Neither Selena nor Dylan

2c Represent proportional relationships by equations

Selena and Dylan studied the data in the table. They each wrote an equation to represent the relationship between the number of students and the number of pizzas ordered. Who is correct?

BOTH are correct

2c Represent proportional relationships by equations

Selena and Dylan studied the data in the table. They each wrote an equation to represent the relationship between the number of students and the number of pizzas ordered. Who is correct?

BOTH are correct

​Write this somewhere in your journal with the 7rp2 notes

Open Ended

Determine what the value of A means in each problem.

2d Explain what a point (x,y) on the graph of a proportional relationship means in terms of the situation

Determine what the value of A means in each problem.

Let's go back and talk about Percents

You should have notes in your journal.

Dropdown

​

Select answer

÷ ​ ​

Select answer

= percent

Dropdown

​

Select answer

⋅​

Select answer

=part

Dropdown

​

Select answer

÷​

Select answer

=whole

Percentages are a rate per 100.

Percentages are fractions that always have 100 as the denominator.

We use % as the symbol to represent percents

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Finding Percents of a Number:Method One

Finding Percents of a Number Method Two

1.Write the percent as a decimal by moving the decimal two places to the left in the percent

(35% ----> 0.35)

2 Multiply the quantity times the decimal

(0.35 x 80 = 28)

Finding a Whole Given % and Part

Examples:

• 5 is 10% of what number?

• There are 16 boys in the classroom. This is 80% of the class. How many total students are in the classroom?​

  • Here, we have a part and a percent. We know we have a part because percent is always out of 100%. We do not have 100% in these type of problems!​ The problems are saying the number we have is that percentage.

Finding Whole Given Part and %

Example: 5 is 10% of what number?

• This problem is stating 5 = 10%. We should recognize that ​since

  5 = 10%, we are missing the whole number.

• Step 1: write your equation of % x whole = ​part

  • 10% x whole = 5

• ​Step 2: change your percent into a decimal

Finding whole given part and %

Finding whole given part and %

Some text here about the topic of discussion

How Do I Know Which Problem is Which?

Finding Percent of a Number vs Finding a Whole Given Part and Percent

• Finding a percent: the problem gives you a percent and a number. The number is the whole number and we are trying to find what number the percentage represents. What is 10% of 100. The word of means what part of 100 is 10%

Finding Whole Given Part and Percent

• Here, the Percent is the number given. 20 is 10% of what number?

  • The sentence is saying 20 = 10%...we know that percent is out of 100% so 20 is not the whole. It is also saying that of what number? Meaning the missing number is the big/whole number!

​

Multiple Choice

Write .506 as a percent.

• 5.06%
• 506%
• 50.6%
• 500.6%

Multiple Choice

What is 125% of 84 ?

• 105
• 188.5
• 473.4
• 356.7

Multiple Choice

What is 30% of 80?

• 30
• 24
• 2.4
• 56

Multiple Choice

What is 90% of 250?

• 245
• 225
• 255
• 244.33

Multiple Choice

Valerie answered 28 problems on her test correctly. If Valerie correctly answered 80% of the problems on the test, then how many problems were on the test?

• 22 problems

• 25 problems

• 35 problems

• 36 problems

Multiple Choice

You are downloading a program onto your computer that is 85 megabytes. As you are working, you notice that only 60% of the program has been downloaded so far. How many megabytes of the program have been downloaded so far?

• 48 megabytes

• 51 megabytes

• 54 megabytes

• 56 megabytes

Multiple Choice

The movie theater has 250 seats. 225 seats were sold for the current showing. What percent of seats are sold?

• 10%

• 20%

• 80%

• 90%