Up next in 10
Part, Whole And Percent: Using The Percent Proportion
In this lesson, we'll learn hot to use and apply the percent proportion to solve real world problems.
Chapters:
00:00 Introduction
00:46 How To Find the percentage
05:28 How to find the part
08:20 how to find the whole
Show More Show Less View Video Transcript
0:00
uh we doing SE section 7.3 which is
0:03
using the percent proportion we done
0:06
with uh 7.2 which was fraction decimals
0:09
and percentages we're done with that now
0:10
we're going to do the percent
0:14
proportion that is not again that's not
0:17
hard
0:20
tomorrow F that's enough I'm talking
0:23
wait the t is on Friday Friday but
0:25
tomorrow we're going to have a um I
0:27
don't like you preest all right I'm
0:30
going to give you a review for it so now
0:31
we're going to talk about the percent
0:32
proportion okay so percent proportion
0:35
what is it right so it's
0:38
basically in this in the nutshell part
0:40
over a whole or this is percent of 100
0:44
right so for example how do we use it if
0:48
I ask you a question here for example 12
0:50
is 1% of 32 I want to know what 12
0:55
represent in terms of a percentage so
0:57
how would I solve that if I say to you
1:00
12 is what per of 32 listen carefully
1:04
here I'm asking a specific question I
1:05
want to find the percent right I know
1:07
that 12 is a number and also know that
1:10
32 is a bigger number right it's a 12 is
1:13
part of a whole number the whole number
1:15
is 32 and I want to know in terms of
1:18
percentage what does 12 represent in
1:20
terms of percentage when it comes to 32
1:23
so how do I solve that right this is
1:26
what we're going to try to do here I
1:27
know that 12 is a number I know that 32
1:29
is number but I want to know what would
1:32
12 represent as part of 32 let me give
1:36
you another question so for example
1:38
right if I take my whole body right I'm
1:41
100% right this is 100% it's just me one
1:43
right so from here to here you have a
1:47
portion right so I want to know this
1:49
portion here of my body how much ises it
1:51
represent out of my my whole body 50% is
1:55
half of it right 50% so that's what we
1:57
are trying to do here so 12 2 is a
2:00
number and then 12 is part of that so
2:03
how much does 12 take out of 32 in terms
2:06
of percentage what does it represent
2:09
okay so to do that there's a way to
2:11
solve it right so we know that we want
2:13
to know what 12 over 32 mean so we going
2:17
12 equals to
2:19
what x 100 thank you very much right
2:22
again it's just redundant information
2:24
we've done it before so that's what the
2:26
thing is the key here to this problem is
2:29
understanding what this is asking you
2:31
need to be able to understand that right
2:33
so that's where the trick is going to
2:34
come is do you understand what they
2:36
asking they're saying 12 is 1% of 32 so
2:40
if I see this I know all right they want
2:43
to know how much does 12 represent in 32
2:45
in terms of percentage does that make
2:46
sense right so this is what we're doing
2:49
here and we're going to use what the
2:50
cross multiplication again so this is
2:54
12200 = 32x and I'm going to divide it
2:57
by 32 this would you do you mind put
2:59
this the calcul and tell me how much
3:00
this is me yeah or anybody that has a
3:03
calculator 37.5 all right so 37.5
3:08
what percent right we don't forget the
3:10
symbol we have to make sure we have the
3:12
symbol
3:14
right
3:15
remember you took out like half point if
3:18
you didn't put a symbol on some of the
3:19
things because we need to understand
3:21
proper notation right so therefore I
3:25
would say that 12 to answer the question
3:28
is what is tell 7.5% of what of 32 does
3:32
that make sense right 12 is 37.5% of 32
3:37
let me ask you a question that has to do
3:38
with this classroom here right so if I
3:41
want to say
3:43
girls are what per of this entire class
3:46
how would you solve this girls have 1%
3:49
of this entire
3:50
class NS so four n so how would you how
3:54
would you set that
3:57
93 that's right 9 13 = x 100 this is how
4:02
we solve it right because we know there
4:03
are 13 students in total this morning
4:06
because we have one missing and amongst
4:08
those 13 there nine girls so now we
4:10
going to solve it so now go ahead and
4:11
tell me what's the percentage 12 how
4:14
what you get uh 69.
4:18
23769 all right so basically let's say
4:19
about 69 3% right so there's more girls
4:23
on boys so that means you boys have a
4:25
lot of options
4:27
right just a lot of options for older
4:30
than all of them you guys have a lot of
4:34
options you can't be picking why you
4:36
cracking your
4:38
knuckles I'm
4:40
just you have a lot of options so
4:42
instead unless you guys are
4:49
interested
4:50
[Music]
4:52
really I think if I did a real survey if
4:55
I can see your heart I'm sure every
4:57
single one of you guys is secret my room
4:59
in this classroom I know
5:05
y all right
5:09
now
5:12
always all right that's
5:14
enough so now we know how to find a
5:17
percent right so now the next question
5:19
is find the part right find the part so
5:23
now I'm asking what number is 15% of
5:26
450 right what number is 15% of 450 how
5:31
do I set that up yeah I was good would
5:34
be x
5:36
450
5:38
15 all right did you understand that
5:41
listen to this yes right so what number
5:44
is 15% of 450 this is how you set it up
5:47
we want to find a number that represent
5:49
15% of 450 we don't know what it is but
5:52
we know that only 15% so we basically
5:55
still using the same rule right so X
5:58
over 450 is equal to 15 100 thank you by
6:01
the way right so this is what this is
6:03
asking so now your question the question
6:06
to this problem is comprehension
6:08
understanding what is being asked of you
6:10
right
6:17
so so for example I I can find out I say
6:21
69% of this
6:22
classroom is all girls right find how
6:26
many girls we have in this classroom I
6:28
mean anybody we got right just count
6:30
right but if you didn't have that visual
6:32
how would you do it there's there's 13
6:34
students right now and that's say
6:36
69% of
6:38
this
6:39
students I would know there's more so I
6:42
don't have to do the math we can do the
6:43
math and right so this is how you do the
6:46
math here so what number is 15% of 450
6:49
we are trying to find a number that is
6:51
15% of 450 it's obviously a smaller
6:53
number if you ever do this and you find
6:55
something bigger you know you did
6:56
something wrong because it's only 15%
6:58
right I want to know what number
7:01
represent 15% of 450 so I'm going to to
7:03
go x 450 = 15 100 and then I can solve
7:07
for x right so I'm going to use the
7:09
cross multiplication again I get 100 x
7:12
450 * 15 is equal to what so going put
7:15
that in calculator I what is it um
7:20
6,750 7 what 50 all right and now I want
7:24
to find I divide by 100 right so X is
7:28
equal to what 6 is
7:30
7.5 5% so not per no not perc why is it
7:35
not perc because it's just a number we
7:36
want to know what number represent 15%
7:40
of 450 I'm not looking for the
7:41
percentage I'm looking for the number
7:42
does that make sense we have to
7:44
understand the ter is right so it's not
7:47
67.5% it's just 67.5 now I know that
7:50
67.5 is what is 15% of 450 does that
7:54
make sense so 67.5 is 50% of 450 and
7:58
then I know that 50% of 450 is 67.5 so
8:03
you have to understand the difference
8:04
between the percentage the part and the
8:07
whole right and now here now we want to
8:09
find the whole right 78 is 60 60% of
8:13
what number we want to find that same
8:16
way it's
8:18
788 = to 60 100 60 over 100 there you go
8:23
right so now we want to find the whole
8:25
we know the qu we know that 78 is 60% of
8:28
a number we don't know that number that
8:30
number is X but we can use again the
8:33
same rule with 60 100 we are told that
8:37
60% of that number is 78 let's find the
8:40
number right so now we use this again
8:43
use a cross multiplication so it's
8:46
7800 = 60x and then 5 find X we divide
8:50
by what 60 right what's that equal 13 so
8:54
what is it 13 130 right so therefore the
8:59
the number that 6 78 is 6% of is 130
9:04
right so this whole section only deals
9:07
with understanding the percent the part
9:10
and the hole the three main things right
9:13
so in the first one to recap we we were
9:15
given the number and we wanted to know
9:18
how much it represent in terms of
9:19
percentage of a bigger number and we use
9:22
again the same rule that we're going to
9:23
be using here we have the we want to
9:25
find the part we have the percentage we
9:27
know that the percentage is 15% and the
9:29
number the whole is 450 we want to know
9:32
what number is that again the same
9:34
principle and then lastly now we have
9:37
the part of the number we have the
9:38
percentage want to know what the actual
9:40
number is we use this all right so three
9:43
simple step this is why kind of see only
9:45
took us like 10 15 minutes now tomorrow
9:48
I'm not going to give you any homework
9:49
today for it because we have a test on
9:51
Friday so what I'm going to do we're
9:53
going to stop here I'm going to give you
9:55
tomorrow we're going to work on uh test
9:57
reviews chapter uh chapter 6
9:59
rights and St and then Friday we have
10:02
our test and then next week we're going
10:04
to do some homework on this one all
10:05
right that's
10:07
it y we're done
#Teaching & Classroom Resources
#Children's Interests
#Calculators & Reference Tools
#Mathematics
#Statistics