Solving Algebraic Proportions

Solving Algebraic Proportions

Poll

How are you feeling today?

• Great

• Good

• I'm okay

• Mehh

• Bad

Which one doesn't belong?

• 1:7 doesn't belong because ____.

• 2:14 doesn't belong because ___.

• 3:11 doesn't belong because___

• 7:49 doesn't belong because ___.

Proportions & Ratios

Ratios use the symbol :
For example 5:10 is a ratio but it can also be written as a proportion

 $\frac{5}{10}$  . In the example,  $\frac{5}{10}$  can be simplified to  $\frac{1}{2}$  . Therefore, the ratio can also be written as 1:2

Simplify the ratio and write it as a proportions

• Simplify the ratio, (5 can be factored out of both 15 and 25)

• 3:5

• Now that the ratio is simplified, I can write my proportion

•  $\frac{3}{5}$  

Your turn!

Simplify the ratio

Multiple Choice

Simplify the ratio 9:27

• 1:9

• 1:3

• 3:1

• answer is already simplified

Multiple Choice

Are the following equations equivalent?

6:10 and 18:30

• yes

• no

Solving Simple Proportions

• Cross multiply

• Divide

Multiple Choice

Solve:

• 1

• 4

• 10

• 5

Multiple Choice

Solve:

• 4

• 32

• 2

• 9

Multiple Choice

Solve:

• 2

• 9

• 35

• 7

How would we solve this proportion?

Use what you KNOW!

• Cross multiply

• Simplify

• Isolate the variable (add or subtract)

• Simplify

• Divide

• Simplify

Let's go back to this problem.....What do we do first?

Now we simplify...What can I simplify?

Now we need to start ISOLATING the variable....What is my next step?

Simplify

What is my next step?

Now Simplify!

Multiple Choice

Solve:

• 3

• 4

• -7

• 15

Multiple Choice

Solve:

• -9

• -28

• 9

• 4