September 23, 2013
Ratios!
September 23, 2013
Ratios can be written 3 ways
September 23, 2013
As a fraction
example 17
25
September 23, 2013
As a fraction
example 17
25
This could mean there were 17 boys at the roller
rink and 25 girls. The ratio of boys to girls at
the roller rink was 17 to 25.
September 23, 2013
As a fraction
example 17
25
This could mean there were 17 boys at the roller
rink and 25 girls. The ratio of boys to girls at
the roller rink was 17 to 25.
The ratio of boys to girls would not be 25
17
September 23, 2013
As a fraction
example 17
25
This could mean there were 17 boys at the roller
rink and 25 girls. The ratio of boys to girls at
the roller rink was 17 to 15.
The ratio of boys to girls would not be 25
17
What would that ratio represent?
September 23, 2013
Right!
Girls
to
Boys
September 23, 2013
Another way to write a ratio is with the
word "to"
September 23, 2013
Another way to write a ratio is with the
word "to"
If you have 10
shirts and 6 pair
of pants, the
ratio of pants to
shirts would be...
September 23, 2013
3 to 5
What????
September 23, 2013
Right!
Reduce!
September 23, 2013
The last way to write a ratio is
with a colon.
It is just like writing the word
"to".
If I send 15 text messages and make 5
phone calls, my text to call ratio could be
written as 15:5, which reduces to 3:1
September 23, 2013
Lets Practice!
September 23, 2013
A Rate- compares 2 different
quantities measured in
different units
A Unit Rate-is a rate per single
unit--a rate with a 1 as the
denominator.
September 23, 2013
Examples:
The last way to write a ratio is
with a colon.
I can travel 40 miles on 2 gallons of
gas...
It is just like writing the word
"to".
40 miles to 2 gallons is a rate
If I send 15 text messages and make 5
20 miles
tocalls,
1 gallon
is to
a call
unitratio
rate
phone
my text
could be
written
as 15:5, which reduces to 3:1
written
20mi/g
September 23, 2013
I drink 100 ounces of water in 5 days...
The last way to write a ratio is
ounces and days are two different units, so 100
with a colon.
ounces:5 days is a rate.
The unit It
rateiswould
20ounces/day
justbelike
writing
the word
"to".
If I send 15 text messages and make 5
phone calls, my text to call ratio could be
written as 15:5, which reduces to 3:1
September 23, 2013
I drive
1515
miles
I can
travel
miles
20 is
The last way to
write in
a ratio
in 20 minutes.
with a colon.
minutes.
It is is
just
like writing the word
Why
this
Why is this considered
a
"to".
considered a
rate?
If I send 15 text messages and make 5
rate?
phone calls, my text to call ratio could be
written as 15:5, which reduces to 3:1
September 23, 2013
How
can you
turn in 20
I can
travel
15
miles
The last way to write a ratio is
it intowith
a unit
a colon.
minutes.
rate?
It is just like writing the word
Why is this considered
a
"to".
rate?
If I send 15 text messages and make 5
phone calls, my text to call ratio could be
written as 15:5, which reduces to 3:1
September 23, 2013
I can travel 15 miles in 20
minutes.
UnitRate-a rate per
single unit--or a rate
a 1 as the
way with
to
write
a ratio
denominator.
The last
Divide!
Why is this considered a
with a colon.
rate?
is
For example,
If Ilike
drinkwriting
100 ounces
ofword
It
is
just
the
miles divided
byhow
20
water in 5 days,
much can
I drink in one
"to".
15
day?
minutes is
.75 miles/min
If I send 15 text messages and make 5
phone calls, my text to call ratio could be
written as 15:5, which reduces to 3:1
September 23, 2013
UnitRate-a rate per
single unit--or a rate
a 1 as the
way with
to
write
a ratio
denominator.
Lets Practice
I can travel 15 miles in 20
minutes.
The last
Why is this considered a
rate?
is
with a colon.
For example,
If Ilike
drinkwriting
100 ounces
It is just
theofword
water in 5 days, how
much can
I drink in one
"to".
day?
If I send 15 text messages and make 5
phone calls, my text to call ratio could be
written as 15:5, which reduces to 3:1
September 23, 2013
Identifying and Writing
Proportions
September 23, 2013
Equivalent ratios: ratios that can be
SIMPLIFIED to the same thing
Example of equivalent ratios:
because both can reduce to
September 23, 2013
Proportion: an equation stating that two
ratios are equivalent.
*If two ratios are equivalent, they are said
to be proportional to each other
September 23, 2013
Determine whether the ratios are proportional
1.
2.
3.
4.
5.
September 23, 2013
Find a ratio equivalent to each ratio. Then use the ratios to
write a proportion.
6)
9)
7)
8)
September 23, 2013
Complete the table of equivalent ratios
angelfish
tiger fish
September 23, 2013
Homework:
p 276 # 5-8 all, 21,24,34
p 285 # 14-30 even, 39
Payday #6 will be NEXT CLASS PERIOD
(Fri/Mon). Lesson 5-1 practice B wksht,
p 276, p285 will be collected.