Up next in 10
We have just finished chapter 5 in which we dealt with equations, multi step equations, and several wrinkles of inequalities. We'll now start chapter 6 and our first lesson will cover operations with ratios.
Chapters:
00:00 Introduction
03:33 How to write a ration in simplest form
06:59 Ratios involving measurement
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0:00
so we're going to talk about ratios
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right so we finished chapter five so and
0:04
now we're going to talk about ratios and
0:05
the question is why do we need ratios we
0:08
need it because they're used to do what
0:10
they're used to compare quantities so by
0:15
definition a ratio is a comparison of
0:17
two quantities by division all right so
0:21
this is why we use ratio yes a lot of
0:24
times when um they're saying what ratios
0:26
are in real life it's a lot of like
0:28
baking and stuff yeah well
0:31
ratio you use it in like a lot of B you
0:33
say baking is that what you said yeah
0:34
baking yeah right so you can use them in
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baking you can use them in a lot of
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things right for example if I wanted to
0:41
know the ratio of boys to girls in this
0:43
classroom what would it be said 9 9 to
0:47
four about N9 I think it's uh no we have
0:51
we it's 14 of you guys right so it's 10
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to
0:55
four so 9 and four all right so it's 9
0:57
and four we don't have everybody here so
0:59
yeah is not here not here right so if I
1:03
was to find that ratio it would be 94
1:05
and if I was say the ratio of boys to
1:07
girls be 4 to n so there's three ways to
1:10
write a ratio right you can have the two
1:14
dot dot five that's one way to write it
1:17
2 to five or 2 to five like this 2 to
1:22
five okay or simply you can just write
1:25
it as a fraction 2 over five so there
1:27
like three main ways to write a ratio
1:30
okay 2 do do 5 2 to 5 or 2 to five yeah
1:36
um so the first number would always
1:38
beator yeah the first number is always a
1:41
numerator good observation right A to B
1:44
if his letters a to b or A over B right
1:49
so if I say for example what's the ratio
1:52
of um pencils to pains in your book bag
1:56
oh Z to zero Z
2:00
0 to Z that's you know that 0 to0 is
2:04
does not exist it's called in
2:06
determination you have
2:07
that1
2:09
01
2:11
what you have you can't have 0.1 pencils
2:14
that's
2:15
impossible one all right so what about
2:18
the ratios of the ratio of
2:21
um sneakers to dress
2:24
shoes zero to zero what about o boots to
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sneakers
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all
2:39
right I Boots the isue of those who love
2:42
mine from those who hate
2:49
m is that
2:51
so wow all right only so just because I
2:56
think I'm going to give her extra credit
2:57
then because she's the only one I love
2:59
you can't do
3:02
that do that why do you mean I can I'm
3:05
enti to do that I can make that decision
3:08
I can take that fortive she's crazy I'm
3:11
I'm win my right to do
3:14
iter I
3:19
don't but I don't
3:22
like okay so now the first thing we want
3:25
to do is we're going to learn how to
3:27
write ratios in their simplest form
3:29
right we've already done stuff like this
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in the previous chapters we've learned
3:33
how to to do what how to simplify
3:35
fraction so it's not going to be nothing
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new the only things that change here is
3:38
that we call them ratios but it is the
3:40
same thing right for example Express the
3:43
ratio 12 baskets in 18 attempts as a
3:47
fraction in its simplest form explain
3:50
its meaning so how would you do that how
3:52
would you solve this problem let's say
3:54
you went and play your basketball game
3:56
and you shot 18 times and you only made
3:58
12 shots right so how would you explain
4:01
Express that ratio yeah 12 12 18 right
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be 12 gabri I can hear your voice
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here 12 to8 right now they saying that
4:13
Express Express this as a fraction so we
4:15
want this in fractional form so how
4:17
would it be then it be 12 over what 18
4:20
12 over 18 and then I want us to
4:23
simplify that right simplify we're not
4:26
going to leave it like this we're going
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to simplify yes
4:30
divided by what three three all right
4:33
that's a good that's a good way to start
4:34
three so we get four over 6 can we go
4:38
any further yes yes what two two right
4:42
two so we get what 2/3 two over3 so how
4:47
how would you explain this if I want you
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to explain this ratio what does that
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mean in terms of a basketball player
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since you guys you play basketball Caleb
4:57
so two to three so how would you explain
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it two or three made percent how would
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you explain that made out of three two
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two shot made out of what three is that
5:07
a good percentage or that yes it's
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pretty good right I want that guy on my
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team two he makes two shots out of three
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I want him on my team right
5:17
yeah I have you sit on the bench for a
5:20
little bit until you
5:21
get right so two to three so that means
5:24
it makes two baskets out of three shot
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attempt all right so this is how you
5:29
explain this now next example 10 out of
5:33
30 Americans own MP3 player
5:36
right so what does that mean so how
5:39
would you express this ratio as a
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fraction in it simplest
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form and explain its meaning 10 out of
5:47
uh 30 yeah you WR 10 do 30 right what
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that's 10 do3 or now we want it as a
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ratio as a fraction we want it as a
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fraction so how you 10 over 30 and then
6:01
what does that give you simplify divide
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by 10 divide it by 10 right got one
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three what does that
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mean huh what does that mean explain it
6:14
every one out of three
6:16
people one people own the MP3 player
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right do you know what the MP3 player is
6:22
right
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oh MP3 player you remember those uh like
6:27
iPods or something yeah the iPod at the
6:30
time iPad were like MP3 player back back
6:33
then it was big thing right when they
6:35
came out and then the iPhone came and
6:37
then blew all of that out of the
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building right so that's
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a yeah
6:45
so so now the next thing we going to
6:47
learn how to do which is a little bit
6:49
now complicated is what she mentioned
6:51
right we talk about we use this kind of
6:54
stuff in baking now I'm going to talk
6:56
about ratios involving measurement right
6:58
measurement
7:01
you cry anybody right example we want to
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try to express the ratio of 8 O to 3 lb
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as a fraction in its simplest form so
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how would you do this one here 8 oz to 3
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lb 8 8 over three all right that's a
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good start right 8 over three but can we
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do
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this what do we have we have what ounces
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and we have pounds so what is the what
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is the issue here what is the problem
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here different me there two different
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things right so since if you're cooking
7:37
right and you have this so how would you
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try to hurt yourself so you know exactly
7:41
what the ratio is measure out8 o and
7:44
then measure out three measure so we
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have to turn there's two options we have
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to turn pounds into what ounces so one p
7:53
is equal to how many
7:55
ounces we know that one pound who knows
7:58
the ratio what what's the one is how
8:00
many ounces the equivalent of what 1
8:02
pound 16 so 16 * 3 we have to memorize
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16 I give it to you so one pound is the
8:08
equivalent of how many ounces who knows
8:10
16 16 16 o you guys know better than I
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do bro I didn't know
8:15
that right so one pound is equal to 16
8:18
oz right but how many pounds do we have
8:22
3 lb so why don't we just convert the 8
8:24
oz to half a pound we can do that too
8:27
there's two options right we can do that
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too we got to turn the 3 lb into O So 3B
8:32
equal to how many
8:34
o 3 lb will be what be 3 * what 3 * 16 o
8:40
which is
8:41
basically 48 oz right now we can find
8:45
this ratio because both of these uh
8:48
units both of these um quantities have
8:50
the same unit now we have 8 O over 48 O
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So now that's going to be
8:57
8 over 48 and because they are both
9:01
ounces right so now we can do the ounces
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and then the ounces are going to cancel
9:06
out so now we divide by eight be one
9:09
over six so that ratio becomes one 2 six
9:14
right this is probably one of the
9:15
easiest chapters in the book pretty much
9:19
right so now what I want you to do is I
9:20
want you to go to your textbook if you
9:22
have it and we're going to work on 1
9:24
through 15 we have plenty of time yet on
9:27
page um 26 6
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267 page
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266 267 this is a pretty easy
9:39
section it's
9:41
F your fun is very much
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