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Part, Whole And Percent: Using The Percent Proportion
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Feb 20, 2025
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
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0:00
uh we doing SE section 7.3 which is
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using the percent proportion we done
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with uh 7.2 which was fraction decimals
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and percentages we're done with that now
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we're going to do the percent
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proportion that is not again that's not
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hard
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tomorrow F that's enough I'm talking
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wait the t is on Friday Friday but
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tomorrow we're going to have a um I
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don't like you preest all right I'm
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going to give you a review for it so now
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we're going to talk about the percent
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proportion okay so percent proportion
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what is it right so it's
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basically in this in the nutshell part
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over a whole or this is percent of 100
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right so for example how do we use it if
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I ask you a question here for example 12
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is 1% of 32 I want to know what 12
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represent in terms of a percentage so
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how would I solve that if I say to you
1:00
12 is what per of 32 listen carefully
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here I'm asking a specific question I
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want to find the percent right I know
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that 12 is a number and also know that
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32 is a bigger number right it's a 12 is
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part of a whole number the whole number
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is 32 and I want to know in terms of
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percentage what does 12 represent in
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terms of percentage when it comes to 32
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so how do I solve that right this is
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what we're going to try to do here I
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know that 12 is a number I know that 32
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is number but I want to know what would
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12 represent as part of 32 let me give
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you another question so for example
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right if I take my whole body right I'm
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100% right this is 100% it's just me one
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right so from here to here you have a
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portion right so I want to know this
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portion here of my body how much ises it
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represent out of my my whole body 50% is
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half of it right 50% so that's what we
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are trying to do here so 12 2 is a
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number and then 12 is part of that so
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how much does 12 take out of 32 in terms
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of percentage what does it represent
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okay so to do that there's a way to
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solve it right so we know that we want
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to know what 12 over 32 mean so we going
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12 equals to
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what x 100 thank you very much right
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again it's just redundant information
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we've done it before so that's what the
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thing is the key here to this problem is
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understanding what this is asking you
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need to be able to understand that right
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so that's where the trick is going to
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come is do you understand what they
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asking they're saying 12 is 1% of 32 so
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if I see this I know all right they want
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to know how much does 12 represent in 32
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in terms of percentage does that make
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sense right so this is what we're doing
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here and we're going to use what the
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cross multiplication again so this is
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12200 = 32x and I'm going to divide it
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by 32 this would you do you mind put
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this the calcul and tell me how much
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this is me yeah or anybody that has a
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calculator 37.5 all right so 37.5
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what percent right we don't forget the
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symbol we have to make sure we have the
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symbol
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right
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remember you took out like half point if
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you didn't put a symbol on some of the
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things because we need to understand
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proper notation right so therefore I
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would say that 12 to answer the question
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is what is tell 7.5% of what of 32 does
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that make sense right 12 is 37.5% of 32
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let me ask you a question that has to do
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with this classroom here right so if I
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want to say
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girls are what per of this entire class
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how would you solve this girls have 1%
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of this entire
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class NS so four n so how would you how
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would you set that
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93 that's right 9 13 = x 100 this is how
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we solve it right because we know there
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are 13 students in total this morning
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because we have one missing and amongst
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those 13 there nine girls so now we
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going to solve it so now go ahead and
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tell me what's the percentage 12 how
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what you get uh 69.
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23769 all right so basically let's say
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about 69 3% right so there's more girls
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on boys so that means you boys have a
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lot of options
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right just a lot of options for older
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than all of them you guys have a lot of
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options you can't be picking why you
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cracking your
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knuckles I'm
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just you have a lot of options so
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instead unless you guys are
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interested
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[Music]
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really I think if I did a real survey if
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I can see your heart I'm sure every
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single one of you guys is secret my room
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in this classroom I know
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y all right
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now
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always all right that's
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enough so now we know how to find a
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percent right so now the next question
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is find the part right find the part so
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now I'm asking what number is 15% of
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450 right what number is 15% of 450 how
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do I set that up yeah I was good would
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be x
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450
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15 all right did you understand that
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listen to this yes right so what number
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is 15% of 450 this is how you set it up
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we want to find a number that represent
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15% of 450 we don't know what it is but
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we know that only 15% so we basically
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still using the same rule right so X
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over 450 is equal to 15 100 thank you by
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the way right so this is what this is
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asking so now your question the question
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to this problem is comprehension
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understanding what is being asked of you
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right
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so so for example I I can find out I say
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69% of this
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classroom is all girls right find how
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many girls we have in this classroom I
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mean anybody we got right just count
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right but if you didn't have that visual
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how would you do it there's there's 13
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students right now and that's say
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69% of
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this
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students I would know there's more so I
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don't have to do the math we can do the
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math and right so this is how you do the
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math here so what number is 15% of 450
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we are trying to find a number that is
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15% of 450 it's obviously a smaller
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number if you ever do this and you find
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something bigger you know you did
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something wrong because it's only 15%
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right I want to know what number
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represent 15% of 450 so I'm going to to
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go x 450 = 15 100 and then I can solve
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for x right so I'm going to use the
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cross multiplication again I get 100 x
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450 * 15 is equal to what so going put
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that in calculator I what is it um
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6,750 7 what 50 all right and now I want
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to find I divide by 100 right so X is
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equal to what 6 is
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7.5 5% so not per no not perc why is it
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not perc because it's just a number we
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want to know what number represent 15%
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of 450 I'm not looking for the
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percentage I'm looking for the number
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does that make sense we have to
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understand the ter is right so it's not
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67.5% it's just 67.5 now I know that
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67.5 is what is 15% of 450 does that
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make sense so 67.5 is 50% of 450 and
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then I know that 50% of 450 is 67.5 so
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you have to understand the difference
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between the percentage the part and the
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whole right and now here now we want to
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find the whole right 78 is 60 60% of
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what number we want to find that same
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way it's
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788 = to 60 100 60 over 100 there you go
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right so now we want to find the whole
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we know the qu we know that 78 is 60% of
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a number we don't know that number that
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number is X but we can use again the
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same rule with 60 100 we are told that
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60% of that number is 78 let's find the
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number right so now we use this again
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use a cross multiplication so it's
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7800 = 60x and then 5 find X we divide
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by what 60 right what's that equal 13 so
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what is it 13 130 right so therefore the
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the number that 6 78 is 6% of is 130
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right so this whole section only deals
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with understanding the percent the part
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and the hole the three main things right
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so in the first one to recap we we were
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given the number and we wanted to know
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how much it represent in terms of
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percentage of a bigger number and we use
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again the same rule that we're going to
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be using here we have the we want to
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find the part we have the percentage we
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know that the percentage is 15% and the
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number the whole is 450 we want to know
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what number is that again the same
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principle and then lastly now we have
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the part of the number we have the
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percentage want to know what the actual
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number is we use this all right so three
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simple step this is why kind of see only
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took us like 10 15 minutes now tomorrow
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I'm not going to give you any homework
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today for it because we have a test on
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Friday so what I'm going to do we're
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going to stop here I'm going to give you
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tomorrow we're going to work on uh test
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reviews chapter uh chapter 6
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rights and St and then Friday we have
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our test and then next week we're going
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to do some homework on this one all
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right that's
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it y we're done
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