Wednesday, November 30 th

Wednesday, November 30th

• Please Complete Warm Up and take out homework (Workbook)• Did you write down your

homework?

WARM UPWrite two equivalent ratios

1. 4:5 2. 6:10

Corny Joke of the Day

Where do fish go on vacation?

Fin-land

Attention!Next Checkpoint is

FRIDAY

Ratio Review

Candy Ratios

In your groups……try to come up with 5 ratios about your

candy!

RateReview

The new movie “Hunger Games” is expected to draw large crowds. Several cinemas have already started making

package deals for movie tickets. In your groups determine which Theater has the

best deal!Mall of Georgia Regal

Cinema

5 tickets for $112

Hollywood 24

7 tickets for $135.60

Homework Answers Can you find my mistakes?

1. 9: 12 or 3:42. 8:16 or 1:23. 10: 94. 10:12 or 5:55. 12:9 or 4:36. 6:9, 12:18, or

2:3 7. 12/14 or 6/7

8. 15/9 or 5/3 9. 15:14 10. 9/12 or ¾

The Word Problems….

Proportions

Can you finish the statement?

1. Basketball is to hoop as soccer ball to ____________.

2. pumpkin is to Halloween as fireworks are to ________________

3. Fish is to water as bird is to _________

These are all

PROPORTIONS!

A proportion is an equation that shows two equivalent ratios.

Read the proportion = as “two is to one as four is to two.”

21__ 4

2__= 4

2__ 8

4__= 2

1__ 6

3__=

21__ 4

2__

Reading Math

Modeling ProportionsWrite a proportion for the model.

number of heartsnumber of stars

48__=

First write the ratio of hearts to stars.

Next separate the hearts and stars into two equal groups.

ContinuedNow write the ratio of hearts to stars in each group.

number of heartsnumber of stars

24__=

A proportion shown by the model is = .48__ 2

4__

Let’s make our own Proportion!

□6 shapes of: _________________

□8 shapes of:__________________

Proportion:

CROSS PRODUCTSCross products in proportions are equal

35__ 9

15___=4

8__ 2

4__= 9

6__ 3

2__= 14

7 __ 2

1__=

8 • 2 = 4 • 4 5 • 9 = 3 • 1516 = 16 45 = 45

6 • 3 = 9 • 218 = 18

7 • 2 = 14 • 114 = 14

This is how you prove proportions!

Question of the dayHow would you find the missing value

to complete proportion

56 18

n

Method #1

Criss Cross and algebra

Steps1. Cross multiply2. Set up equation3. Use inverse

operations to solve for missing variable

56 18

n

Criss-Cross and Solve! Find the missing value in the proportion.

6n 6

___

56__ n

18 __= Find the cross products.

6 • n = 5 • 18 The cross products are equal.

6n = 90 n is multiplied by 6.

90 6

___= Divide both sides by 6 to undo the multiplication.

n = 15

Method #2

Use guess and checkCaution: doesn’t work if the

answer is a fraction!

Think:

6 x what number is 18

So, 5 x that number is n

56 18

n

You Try #1

17 21

p

You Try #2

315 30

r

You Try #3

129 3

n

You Try #4

6 307 a

You Try #5

36 4

x

Real World Application

According to the label, 1 tablespoon of plant fertilizer should be used per 6 gallons of water. How many tablespoons of fertilizer would you

use for 4 gallons of water?

f4 gal

____1 tbsp 6 gal

_____ = Let f be the amount of fertilizer for 4 gallons of water.

f4 gal

____1 tbsp 6 gal

_____ = Write a proportion.

6 • f = 1 • 4 The cross products are equal.

In a proportion, the units must be in the same order in both ratios.

Caution!

tbspgal

___tbspgal

___ =

galtbsp

___galtbsp

___ =or

Continued

f is multiplied by 6.

Divide both sides by 6 to undo the multiplication.

Write your answer in simplest form.

6f = 4

6f 6

___ 4 6

__=

f = tbsp 2 3

__

You would use tbsp of fertilizer for 4 gallons of water.

2 3

__

Word Problem Practice□Each group will be assigned one

word problem□ In your groups you must: Show your proportionShow work to show answer

ExperimentFor most people, the ratio of thelength of their head to their total

height is 1:7. Use proportions to testyour measurements and see if they

match this ratio.