THURSDAY, DECEMBER 1ST o Please Complete warm up
and take out homework (worksheet)
o Did you write down the homework?
Warm UpWrite a rule for each sequence
using “n”1. 15, 24, 33, 222. -11, -15, -19, -24
DID YOU KNOW?!?!?For 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.
CORNY JOKE OF THE DAY
How did the hammerhead
shark do on his quiz?
He Nailed it!
ATTENTION!Next Checkpoint is
FRIDAY
HomeworkAnswers
EquivalentRatios
Equivalent ratios • are ratios that name the same
comparison. • You can find an equivalent ratio by
multiplying or dividing both terms of a ratio by the same number.
CAN YOU MAKE TWO EQUIVALENT RATIOS?!?!
1. 4.
2. 5. 5 to 9
3. 6 : 12
12
23
412
JUMPING JACKS
Number of Jumping Jacks
Equivalent #1
Equivalent #2
Equivalent #3
Time (Seconds)
Rates
WHAT IS RATE?
RATE: compares two quantities that have different units of measure
WHAT IS RATE?
For example:Abbey charges $28 dollars for 3 hours of swimming lessons. David charges $18 dollars for 2 hours of swimming lessons. Which instructor offers a better deal?
HOW DO WE FIND IT?
Divide! Set up your Rate
Abbey: charges $28 dollars for 3 hours of swimming lessons.
Rate= = = 9.33Dollarshours
283
FIND DAVID
Who had a better deal?
Set up your RateDavid: charges _______dollars for _______ hours
of swimming lessons. Rate= = =__________Dollars
hours
YOU TRY!
An 8-ounce bag ____________chips costs $1.68. A 4-ounce bag of __________chips costs $0.88. Which is the better deal?
Example#2
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
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
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
Cross Multiply and Divide
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
CrossMultiply
And Divide!!!!
METHOD #2
Use guess and checkCaution: doesn’t work if the answer is a fraction!
Soooooooooooo
easyyyyyyyyyyy
56 18
n
YOU TRY #1
17 21
p
YOU TRY #2
315 30
r
YOU TRY #3
129 2
n
YOU TRY #4
6 207 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.
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
__
In a proportion, the units must be in the same order in both ratios.
Caution!
tbspgal
___tbspgal
___ =
galtbsp
___galtbsp
___ =or
WHAT DID RUDOLPH DO WRONG?Fives pounds of sugar cookies cost $20 dollars, but he only
needs 3 pounds
5$20 3lbs x
lbs
Top Related