Volume of a sphere | Perimeter, area, and volume | Geometry | Khan Academy

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  • Опубликовано: 12 ноя 2024

Комментарии • 91

  • @mento6
    @mento6 12 лет назад +56

    I am amazed by your computer writing/drawing skills.

    • @cosmicanomaly3403
      @cosmicanomaly3403 7 лет назад +9

      same since he used a mouse, and drawing with a mouse is hard

    • @t00lbox
      @t00lbox 4 года назад +2

      he has a drawing tablet

    • @ryio.0
      @ryio.0 3 года назад +2

      @@t00lbox I Dont Think There Are Drawing Tablets 8Years Ago

    • @maaasmahal
      @maaasmahal 3 года назад

      @@ryio.0 they had some of them boards that they can write on. It’s most likely they will have a drawing tablet

  • @jadenle1190
    @jadenle1190 3 года назад +21

    You’re a lifesaver when it comes to not passing math class🙏🙏🙏🙏

  • @twentynecrybabies8685
    @twentynecrybabies8685 8 лет назад +7

    ugh this guy should get payed his videos are honestly so helpful

    • @diyahegde2019
      @diyahegde2019 6 лет назад +1

      He owns a company for making these vids lol

  • @pierceingram9831
    @pierceingram9831 6 месяцев назад +1

    This helped me further understand volume of a sphere. It also helped me get the peremiter and area of the sphere. I loved the way it showed the thought process and showed what he typed into the calculator also.

  • @NickleJ
    @NickleJ 6 лет назад +15

    It gave me a small chuckle when you said "get out the calculator to get the exact value [of pi]". xD

  • @aryabhanduth1566
    @aryabhanduth1566 4 года назад +35

    Understands *
    Lays in bed making own sums
    *forgets everything*

  • @hiroshih9157
    @hiroshih9157 6 лет назад +10

    0:24 "straight through the centimeter"

    • @amongus282
      @amongus282 3 года назад

      lol i thought i was the only one who noticed that

  • @KILLRXNOEVIRUS
    @KILLRXNOEVIRUS 5 лет назад +12

    *Area circumference volume
    And for a sphere whats circumference or the area all way round called? Or is it the same?

  • @gexwing
    @gexwing 13 лет назад +11

    i suggest you do a video about how to derive such a volume formula (e.g. integrating 1 over the area, in this case in sperical coordinates), i think this would be appreciated.

    • @Romeo.761
      @Romeo.761 6 месяцев назад

      12 years ago. You still remember this?

  • @whosoever_sterling8492
    @whosoever_sterling8492 10 лет назад +13

    THANKKK UUUU

    • @JommPods
      @JommPods 2 года назад +1

      how are you doing in life now?

    • @sabuba47913
      @sabuba47913 5 месяцев назад +1

      @@JommPods how are you doing in life? been 2 years

  • @anishali8186
    @anishali8186 9 лет назад +7

    LOL! You are the only one who explained

  • @shirleyh9800
    @shirleyh9800 5 лет назад +4

    this the best video ever thanks

  • @alvarorevenga9313
    @alvarorevenga9313 2 года назад +3

    Thanks for the video bro, I coudnt understand It till i saw your vídeo, very good explained and clear, i appreciate

  • @howard1beale
    @howard1beale Год назад +1

    7x7x7 = 323
    4/3 x pi squared x 323
    1436.8cm3
    Voilà!

  • @austin4parkour
    @austin4parkour 8 лет назад +4

    quote of 2011: "straight through the centimeter" -Sal Khan

  • @tayleister
    @tayleister 11 лет назад +1

    I needed thus so much

  • @srivatsn00
    @srivatsn00 9 лет назад +1

    Cool, awesome, the best. Its the best...

  • @emmanuelsethcanonigo2112
    @emmanuelsethcanonigo2112 4 года назад +2

    When he said
    Aaand were done
    I was like... Wait already?

  • @mariasjoerdsma8355
    @mariasjoerdsma8355 8 лет назад +1

    thanks

  • @lliaolsen728
    @lliaolsen728 7 лет назад +3

    If you cubed it to get 1436.8, why is the answer 1436.8^3 ? I thought you already used up the "^3" in the initial calculation so what does cubing the number it again do?

    • @ddpr4435
      @ddpr4435 7 лет назад +1

      Llia Olsen I think it'd because the cubed here is refrencing the type of centimeter, not the actual volume. the 3rd power in the original problem is to express the volume of the circle in 3 dimensional space, while the cubic centimeter is just a unit of measurement to measure that space in three dimensions

    • @lordvoldemort5725
      @lordvoldemort5725 6 лет назад +1

      Llia Olsen the centimeters are cubed he puts it there to indicate that the number and centimeters are cubed and you have to put it there

    • @yormom264
      @yormom264 2 года назад +1

      You put the cubed on top of the units. In this case it's cm. It has nothing to do with the calculations. Since, it's volume we are talking about we use "units cubed".

  • @lillith-0909
    @lillith-0909 Год назад

    bro js saved my math grade

  • @timathywise691
    @timathywise691 2 года назад

    Thanks so much 🙏🏼

  • @kaiw.s6053
    @kaiw.s6053 9 лет назад +1

    Thanks :)

  • @steph3172
    @steph3172 3 года назад +1

    ily thank you so much

  • @mahmoodahmed5449
    @mahmoodahmed5449 3 года назад

    Ty

  • @TimDaBoss27
    @TimDaBoss27 11 лет назад +1

    Thanks so much!

    • @JommPods
      @JommPods 2 года назад

      after 9 years hows life now?

    • @TimDaBoss27
      @TimDaBoss27 2 года назад

      @@JommPods hahaha wow that’s crazy! great man

    • @JommPods
      @JommPods 2 года назад

      @@TimDaBoss27 great to hear bro!

  • @kaylamaso798
    @kaylamaso798 10 лет назад +1

    i probaly would've used the calc. so I'm glad he used it. lol :)

  • @RonaldTrumpet7956
    @RonaldTrumpet7956 Год назад

    Thank the lord i found this vid

  • @apex7598
    @apex7598 12 лет назад

    thanks khan

  • @daltonhenderson6276
    @daltonhenderson6276 4 года назад +3

    cant you just use 3.14 for pi

  • @jhayrhex4448
    @jhayrhex4448 2 года назад

    Help plss 😐✌️. How to find percentage using sphere formula?
    What percent increase in volume is achieved by a sphere whose diameter
    increases from 3 cm to 4 cm?

  • @healthyamerican
    @healthyamerican 4 года назад +1

    why doesnt someone modernize this ancient method?

  • @Blaze7439
    @Blaze7439 8 лет назад +2

    Hey! I doubt anyone will answer this since this video is YEARS old but uh, can anyone explain to me why its formula is 4/3?

    • @JagjitBrawler
      @JagjitBrawler 8 лет назад +6

      Lol, that's actually a question that deals with calculus. So, Calculus tells us that volume is the integral of surface area (that itself is a whole other topic of discussion. Basically, if you were to take the surface of the shape and add up an infinite number of rectangles, it would give you volume). The surface area of a Sphere is 4(pi)(r)^2 as you probably already know. So in order to take the integral of the surface area, we make it a function A(x) = 4(pi)x^2 (plugging in r for x). By reversing the power rule (aka finding the antiderivative), you would do (x^(n+1))/(n+1). In our equation that would be (4(pi)x^(2+1))/(2+1) = (4(pi)x^3)/3 which would be the same as 4/3(pi)x^3........this is one of the many formulas that Calculus provides geometry with.

    • @mert446
      @mert446 3 года назад +2

      @@JagjitBrawler I think it would be easier to just say that its the infinite sum of all of the cylinders, by doing:
      integral from -r to +r of (pi * y^2) (dx)
      which is 2 times integral from 0 to +r of root(r^2-x^2)^2 (dx)
      which is (2)(pi) integral from 0 to +r of r^2-x^2 (dx)
      which is (2)(pi) F.Th.Calculus 0-->+r of xr^2-1/3x^3
      which is (2)(pi)(r)(r)^2 - (r)^3/3
      which is (2)(pi)(2/3)(r)^3
      which is (4/3)pi(r)^3

    • @JagjitBrawler
      @JagjitBrawler 3 года назад +2

      @@mert446 so apparently I could do math 4 years ago lmao. Today I don’t even remember how to do chain rule

    • @mert446
      @mert446 3 года назад +2

      @@JagjitBrawler lol

    • @amongus282
      @amongus282 3 года назад

      holy cow, there are these smart people talking about calculus @-@

  • @daltonhenderson6276
    @daltonhenderson6276 4 года назад +3

    this is so confusing im not that smart

  • @fed-ahfed
    @fed-ahfed 2 года назад

    im in grade 6 i have to take part in a natonal grade 6 exam as soon as i saw the formula i instantly got it but thank you for make this vid

  • @why_awesome
    @why_awesome 3 года назад +1

    this was for biology lol

  • @brittaneymcdonald2519
    @brittaneymcdonald2519 6 лет назад

    can it be an approx answer I got 1436.9

  • @fwwryh7862
    @fwwryh7862 5 лет назад +3

    So just use a calculator.

    • @SubscribersWithaFewVideos
      @SubscribersWithaFewVideos 5 лет назад +3

      CENTRA STUDIOS the point is to know the formula. If all you wanted was to know how to calculate big numbers, this isn’t the best source.

    • @amongus282
      @amongus282 3 года назад

      @@SubscribersWithaFewVideos agreed, this is not the best source

  • @ronanrox
    @ronanrox 3 года назад +1

    A sphere doesn't have volume, a ball has. Sphere is "a boundary of a ball", or "the surface of a ball". Shouldn't you be precise with your use of terms?

  • @mashupstyles2389
    @mashupstyles2389 10 лет назад +5

    you shouldn't have used the calculator! :)

    • @SubscribersWithaFewVideos
      @SubscribersWithaFewVideos 5 лет назад +3

      mashup styles why not? thats what calculaters were for right? In the real world, we won’t need to computate for ourselves at all times

    • @amongus282
      @amongus282 3 года назад

      @@SubscribersWithaFewVideos -_- im in flippin middle school tryna pass my test ofc im not gonna cheat using a calculator i need another way to solve this-

    • @JommPods
      @JommPods 2 года назад

      @@amongus282 how are u doing now?

    • @universe00047
      @universe00047 Месяц назад

      ​@@amongus282just work it out on paper

  • @morganatheok4892
    @morganatheok4892 10 месяцев назад

    Thank god imallowed a calculator :/

  • @AntoineVanGeyseghem
    @AntoineVanGeyseghem Год назад

    =o

  • @Frenchorg-bd5hz
    @Frenchorg-bd5hz 7 лет назад +1

    IM NEVER GONNA GET IT

    • @amongus282
      @amongus282 3 года назад

      well.. it's been 3 years- do you get it now XD

    • @JommPods
      @JommPods 2 года назад

      @@amongus282 well its been 4 years i wonder if he gets it now XD

    • @universe00047
      @universe00047 Месяц назад

      Its been 6 years. I wonder if he gets it now XD

  • @ytshorts6959
    @ytshorts6959 7 лет назад

    Not nice

  • @orecreeper2128
    @orecreeper2128 9 лет назад +1

    U talk so fast Speak Slower man!!

  • @Skatr
    @Skatr 4 года назад

    Dude literally did nothing to help. He just put it in the calculator

    • @amongus282
      @amongus282 3 года назад

      he prob got confused too XD

    • @amongus282
      @amongus282 3 года назад

      this vid wont help , this is just the formula which you can get off google

  • @yujiesun1935
    @yujiesun1935 9 лет назад +1

    Thanks :)

  • @uytgfkuyfgoluygokgfkhfgkjh1899
    @uytgfkuyfgoluygokgfkhfgkjh1899 2 года назад

    thanx bro🤝