Garfield's proof of the Pythagorean theorem | Geometry | Khan Academy

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  • เผยแพร่เมื่อ 10 ม.ค. 2025

ความคิดเห็น • 126

  • @nickbarton3191
    @nickbarton3191 9 ปีที่แล้ว +98

    Just goes to show how boring political meetings are that he had to resort to trig for entertainment.

    • @marcoskano4437
      @marcoskano4437 4 ปีที่แล้ว +1

      Trig is fun even more when you start with cálculos

  • @saturn21207
    @saturn21207 6 ปีที่แล้ว +32

    When you think you're eating lasag but you accidentally solve quantum physics

  • @zombieslayer2225
    @zombieslayer2225 5 ปีที่แล้ว +32

    Garfield:*Doodles in a meeting.
    Garfield:*Constructs a trapezoid using three triangles.
    Garfield:*Solves the equation.
    Garfield:*Realizes that he just prove the Pythagorean theroem.
    Garfield: :O

  • @Bakmoon
    @Bakmoon 12 ปีที่แล้ว +8

    Thank you so much for posting this. This is one of my favorite proofs of the Pythagorean theorem along with the Bhasakra proof and the Chinese proof.

  • @javipdr19
    @javipdr19 12 ปีที่แล้ว +7

    i've always wondered how a mathematician (amateur or profesional) feels when he finds a proof for something! It must be great, even i got excited watching this video.

  • @VanBurenOfficial
    @VanBurenOfficial 10 ปีที่แล้ว +8

    James A. Garfield was a great man.

  • @Xclann
    @Xclann 12 ปีที่แล้ว +6

    Search for "Electron Configuration". That's where the 1s 1s^2 2p^6 3s^2... etc. is explained by Khanacademy (Khan himself).

    • @parthibhayat
      @parthibhayat 2 ปีที่แล้ว +1

      Ok?

    • @JamesMac-fd7dx
      @JamesMac-fd7dx ปีที่แล้ว

      2s orbital remains unfilled as a result of shielding

  • @Bobyfototube
    @Bobyfototube 10 ปีที่แล้ว +12

    Thank u Mr president

  • @4gate
    @4gate 9 ปีที่แล้ว +19

    beautiful. so simple

  • @AlexandrBorschchev
    @AlexandrBorschchev 4 ปีที่แล้ว +7

    just imagine garfield's face when he found the proof.
    *EUREKA*

  • @callumvanheerden1530
    @callumvanheerden1530 8 ปีที่แล้ว +27

    Is it just me or is this easier than the other methods

    • @mausam6101
      @mausam6101 5 ปีที่แล้ว +2

      it is/.

    • @marcoskano4437
      @marcoskano4437 4 ปีที่แล้ว +3

      You have seen the square method ? It is much easier than this but this is more fun

  • @thewirelessbrain9331
    @thewirelessbrain9331 8 ปีที่แล้ว +14

    Now THAT is a true masterpiece.

  • @smyleylily
    @smyleylily 12 ปีที่แล้ว +1

    this is a lot easier than the proof in the book. thumbs up

  • @longhorn4500
    @longhorn4500 12 ปีที่แล้ว +4

    But there are still things that need to be proved such as the sum of the angles of a triangle is 180 and the area of a trapezoid is h * (a + b)/2 :)

  • @astroboomboy
    @astroboomboy 12 ปีที่แล้ว +1

    Yeah, I was wondering about that, thanks for answering, I'll check it out. Would be neat to use it in lectures!

  • @viki2133
    @viki2133 8 ปีที่แล้ว +21

    Huh... That's quite simple and it's actually using just geometry for the 7th grade.

    • @viki2133
      @viki2133 8 ปีที่แล้ว +2

      Shane Yaw ?

    • @Myrus_MBG
      @Myrus_MBG 5 ปีที่แล้ว +5

      Dylan Atwater It is a pretty arbitrary to think to create a trapezoid like that, and the solve for the area in two ways. It makes sense why no one would have thought to do that.

  • @StevenEncarnacion
    @StevenEncarnacion 12 ปีที่แล้ว +2

    awesome...good job Mr Garfield!

  • @qszwax57
    @qszwax57 12 ปีที่แล้ว +1

    Do you have a video on the difference between theorems and laws?

  • @Spawnwarrior007
    @Spawnwarrior007 12 ปีที่แล้ว +2

    Thanks Sal you're the best bro!

  • @WiseSquash
    @WiseSquash 5 ปีที่แล้ว +2

    this is so beautiful I almost cried :')

  • @JoeBrenn
    @JoeBrenn 12 ปีที่แล้ว +1

    Very cool, I'll admit I wished that I'd seen the end proof coming a little sooner than I did, but it was very interesting nonetheless. Done perfectly to keep peoples' attention too!

  • @Ensign_Cthulhu
    @Ensign_Cthulhu 12 ปีที่แล้ว

    That is the neatest and easiest Pythagorean proof I've yet seen.

  • @lost50
    @lost50 12 ปีที่แล้ว

    you could also use opposite reciprocal slopes, i.e. b/a and -a/b, to show that's a 90 degree angle

  • @Funney14096
    @Funney14096 10 ปีที่แล้ว +1

    Thanks again!

  • @Nickuncle
    @Nickuncle 12 ปีที่แล้ว

    Honestly, just because you said "mean" for .5(A+B) for the trapezoid I'll actually remember the rule...finally. Thank you.

  • @PillSmasher
    @PillSmasher 11 ปีที่แล้ว

    Any possible way you could elaborate further on this proof by extending the top (a) to be equal to the bottom (b), thus creating a rectangle, then solving for the 4th triangle? From this proof, I've came to the conclusion that theta is equal to 30, and that 90 minus theta equals 60, making the a,b triangles 30,60,90 triangles, and the c triangle is a 45, 45, 90 triangle.

  • @sidyom5068
    @sidyom5068 6 ปีที่แล้ว

    A little bit easier of a way to look at it would be to continue the triangle construction all the way around to make a square of side length (a+b) then noting that the crooked square made by the hypotenuses with side length c has area of c^2. Then you can note that [(a+b)^2 - c^2]/4 = ab/2 which leads very naturally into the pythagorean theorem!

  • @jcc777777
    @jcc777777 12 ปีที่แล้ว

    In this instance: B1 = a , B2 = b and H = a+b

  • @islulison
    @islulison 12 ปีที่แล้ว

    i like this one the most, no moving or anything

  • @chitranshnigam4796
    @chitranshnigam4796 3 ปีที่แล้ว

    I just got to know this and this is so cleverrrr

  • @Gravegore
    @Gravegore 12 ปีที่แล้ว

    You are a wizard sir.

  • @sofiagonzalez-nolde9974
    @sofiagonzalez-nolde9974 10 ปีที่แล้ว +3

    beautifully simple i love it lol

  • @andrewreed5743
    @andrewreed5743 12 ปีที่แล้ว

    What about using this area for a trapezoid (B1+B2)•H/2

  • @Funney14096
    @Funney14096 10 ปีที่แล้ว +44

    Can Obama do this too?

    • @dalawhether6079
      @dalawhether6079 7 ปีที่แล้ว +6

      Funney14096 and Trump?😂😂😂

    • @Burgundian_accel
      @Burgundian_accel 6 ปีที่แล้ว +1

      call Mr Donald Trump to attempt for 1 proof.😃

    • @davidgould9431
      @davidgould9431 6 ปีที่แล้ว +11

      Trump: "Pythagermmm Theorem - FAKE NEWS"

  • @doctorcrazydude
    @doctorcrazydude 12 ปีที่แล้ว

    I just sat there watching the video, not expection anything impressing, but when he just solved the misterious angle I was like: HOLY SH**! I know that sounds nerdy, but it really blew my mind :D Thanks Sal!

  • @ducameana
    @ducameana 12 ปีที่แล้ว

    all the color changing would have been awesome on paper with one of those multicolor clicky pens.

  • @elbay2
    @elbay2 12 ปีที่แล้ว

    Yet ANOTHER proof... cool stuff !!

  • @javed00
    @javed00 12 ปีที่แล้ว

    brilliant explanation

  • @alizaadnan1367
    @alizaadnan1367 6 ปีที่แล้ว +3

    why do u multiply both sides with 2 at 6:56 ???

    • @dataspace8869
      @dataspace8869 6 ปีที่แล้ว +5

      To cancel out those "1/2", which makes clearer the proof

    • @thedt7746
      @thedt7746 6 ปีที่แล้ว +3

      To get rid of the fraction

  • @chaitanyanaik641
    @chaitanyanaik641 7 ปีที่แล้ว

    Wow😍 too simple

  • @esmeraldahernandez1709
    @esmeraldahernandez1709 10 ปีที่แล้ว

    Thanks Helped me out ! :)

  • @XagonogaX
    @XagonogaX 12 ปีที่แล้ว

    Could we have a video that proves e=mc squared?

  • @maevei-j4798
    @maevei-j4798 10 ปีที่แล้ว

    what software do you use to draw and speak at the same time !?!?

  • @MCPickaxe
    @MCPickaxe 4 ปีที่แล้ว +1

    i thought garfield was lasagna guy

  • @danieltambunan5409
    @danieltambunan5409 7 ปีที่แล้ว +2

    Where did you get 2ab on the left side

    • @4ltrz555
      @4ltrz555 6 ปีที่แล้ว +1

      (a+b)^2 = a^2 + b^3 + 2ab

  • @Mintchocolator
    @Mintchocolator 12 ปีที่แล้ว

    So interesting!!

  • @christophersedlak1147
    @christophersedlak1147 8 ปีที่แล้ว

    Thanks!

  • @MonstersSeeMeToo
    @MonstersSeeMeToo 12 ปีที่แล้ว +1

    WHAAAT PYTHAGORAS WASN'T REAL EITHER!!! Whats next? Plato never lived in a cave?

  • @montrast0705
    @montrast0705 8 ปีที่แล้ว

    what program are you using for drawing?

  • @zaixhadouken
    @zaixhadouken 12 ปีที่แล้ว

    I didn't know Garfield did this. Excellent. +1 for Cats

  • @bobsagget823
    @bobsagget823 12 ปีที่แล้ว +1

    nice

  • @nurlatifahmohdnor8939
    @nurlatifahmohdnor8939 2 ปีที่แล้ว

    Page 450
    WILLIAM HENRY HARRISON and BENJAMIN HARRISON (grandfather and grandson).

  • @beru58
    @beru58 ปีที่แล้ว +1

    “In the course of my law-reading I constantly came upon the word ‘demonstrate.’ I thought, at first, that I understood its meaning, but soon became satisfied that I did not…. At last I said, ‘Lincoln, you can never make a lawyer if you do not understand what demonstrate means’; and I left my situation in Springfield, went home to my father’s house, and stayed there till I could give any propositions in the six books of Euclid at sight.”
    That was Abe Lincoln on Euclid's Elements. Many important politicians and leaders understood the importance of mathematics. Napoleon is famous for his method to find the centre of a circle with a compass ONLY. NOT compass and straight edge. No wonder the Declaration of Independence is layed out in many respects as the Elements.

  • @64diamonds99
    @64diamonds99 5 ปีที่แล้ว

    My math teacher sucks at teaching, so I came here.

  • @trymore123
    @trymore123 12 ปีที่แล้ว

    hello there,
    i am thinking if i could use a little bit of your help..
    i am a constant user of khanacademy website.. i use it a lot but i cant seem to find the video(under chemistry) where you've explained aufbau's principle... am basically having a problem understanding the configuration and how use those 1s 1s^2 2p^6 and others... if you could just help me find the particular video or any related ones... it would be great!!
    thanks!

  • @kelvincheng1833
    @kelvincheng1833 9 ปีที่แล้ว

    i just noticed that most of the time, he uses red for side a, blue for side b and yellow for side c in his videos

  • @LiamInviteMelonTeee
    @LiamInviteMelonTeee 4 ปีที่แล้ว

    This reminds me of that clever visual proof on Wikipedia

  • @jacksawhavoc
    @jacksawhavoc 10 ปีที่แล้ว

    There is a proof like this where the two trapezoids form a larger square so (a+b)^2 = 4(ab/2) + c^2 . Is Garfield considered to be responsible for this as well?

  • @trevorstevenson5814
    @trevorstevenson5814 12 ปีที่แล้ว

    I still do not understand why those certain positions of triangles have anything to do with the relationship of side measurements in a right triangle.

  • @ubrax8161
    @ubrax8161 6 ปีที่แล้ว

    Thanks

  • @kremitlol5556
    @kremitlol5556 5 ปีที่แล้ว

    Garfield funny lasagne cat

  • @rauffant
    @rauffant 12 ปีที่แล้ว

    Amazing proof.

  • @charlessmyth
    @charlessmyth 12 ปีที่แล้ว

    James Garfield,: Showing that the House of Representatives is sometimes good for something :-)

  • @paul1964uk
    @paul1964uk 12 ปีที่แล้ว

    Nice proof.

  • @groundhogjugglers
    @groundhogjugglers 12 ปีที่แล้ว

    Nice!

  • @dsb1763
    @dsb1763 12 ปีที่แล้ว

    Garfield was probably as board sitting Congress then as we are now watching CSPAN. Nothing has changed!

  • @miken5771
    @miken5771 9 ปีที่แล้ว

    Genius President.

  • @tmjcbs
    @tmjcbs 6 หลายเดือนก่อน

    This is rather similar to the proof with the square with sides a+b

  • @rozerincagli4021
    @rozerincagli4021 8 ปีที่แล้ว +3

    He was maths teacher before his political career

  • @theimmux3034
    @theimmux3034 4 ปีที่แล้ว

    Wonder if he was just playing around with some geometry and stumbled upon this

  • @jaywaijy
    @jaywaijy 12 ปีที่แล้ว +2

    excellent proof, much more convincing!! Hahaha! I feel like a nerd.

  • @R4G3QUI7
    @R4G3QUI7 12 ปีที่แล้ว

    how can he write so clean with mouse ?

  • @adityaaysola9708
    @adityaaysola9708 3 ปีที่แล้ว

    Often times in life , I ask the question "why?" a lot. And, I would like to apply my philosophy to this problem as well. Why did you construct the trapazoid?

    • @staticchimera44
      @staticchimera44 3 ปีที่แล้ว +2

      He had a feeling in his bones.

    • @thecosmos7671
      @thecosmos7671 2 ปีที่แล้ว +1

      No, it's just that we construct something which we know about, because in a two triangles like this he could not create a square,he could have if it were 4 triangles. So ,he just joined the triangles with a line and found it to resemble a trapezoid,as we know one pair opposite sides are parallel in a regular trapezoid so the corresponding sides of the triangles will be the parallel sides and the sum of the bases of the right triangles will be the height of the trapezoid .
      Since we know the formula of area of a trapezoid i.e 1/2(sum of parallel sides*height)
      We just have to equate the area of the trapezoid tp the sum of areas of three triangles ,the two which we already had and the third we constructed which is an isosceles right triangle with the two equal side lengths to be c ,and when finding out the area
      We have( 1/2)ab+(1/2 )ab 1/2(c^2)=1/2(a+b)(a+b)
      [ the third triangle has base and height both as 6]
      Simplifying, we get the result!👍

    • @kerch00
      @kerch00 2 ปีที่แล้ว

      The way to find the area of a trapezoid using its height and bases is proven, so you can build a proof about the bases and height - which are a, b and c here - in a way which can describe their relation, this ends up with the relationship between a, b and c being a^2 + b^2 = c^2

  • @morgengabe1
    @morgengabe1 11 ปีที่แล้ว

    MS Paint. Use the slanted brushes, not the solid circular ones.

  • @kafumbla
    @kafumbla 12 ปีที่แล้ว

    Lol no he uses a drawing tablet (a Wacom Bamboo tablet). You can find his set-up and gear somewhere on his site

  • @SuperExodus13
    @SuperExodus13 ปีที่แล้ว

    Apparently he did this when he was bored.

  • @GlorifiedTruth
    @GlorifiedTruth 11 ปีที่แล้ว

    I read somewhere that Garfield ripped this proof off from Rutherford B. Hayes.

  • @chezbgone-alpha
    @chezbgone-alpha 12 ปีที่แล้ว

    If anyone notices, this is just half of bhaskara's proof. :)

  • @Klazyo
    @Klazyo 12 ปีที่แล้ว

    sooo awesome

  • @RealistiiC155
    @RealistiiC155 12 ปีที่แล้ว +1

    5:10 "now, how can we also fuc- figure out the area?" :P

  • @morgengabe1
    @morgengabe1 11 ปีที่แล้ว +2

    Favourite US President.

  • @gptrefback
    @gptrefback 12 ปีที่แล้ว

    nice and easy (:

  • @JoshuaIfidi
    @JoshuaIfidi 5 ปีที่แล้ว

    James Garfield's proof of the pythagorean theorem was the 5th proof not the first

  • @abidahasnain2638
    @abidahasnain2638 5 ปีที่แล้ว

    Amazingly WoW !
    Thanks for this ...

  • @oriraykai3610
    @oriraykai3610 2 ปีที่แล้ว

    Did he run on this platform and win?

  • @FrankEgan
    @FrankEgan 12 ปีที่แล้ว

    Garfield discovered a new proof for The Pythagorean Theorem while fiddling around as a member of The House of Representatives. Too bad most members of the current House of Representatives are too bussy doing another kind of fiddling around…

  • @astroboomboy
    @astroboomboy 12 ปีที่แล้ว

    Do you draw with a mouse?

  • @Linqua2112
    @Linqua2112 12 ปีที่แล้ว

    i second more electronics and quantum physics!

  • @ShadowCloud143
    @ShadowCloud143 12 ปีที่แล้ว

    I did not know that.

  • @cajunmane82
    @cajunmane82 12 ปีที่แล้ว

    Your first time hearing about James Garfield is it?

  • @daedricwomack7843
    @daedricwomack7843 6 ปีที่แล้ว

    I thought dis was gonna be Garfield im an idiot

  • @alexgold133
    @alexgold133 9 ปีที่แล้ว +1

    i am so confused

  • @cobyup10
    @cobyup10 2 ปีที่แล้ว

    *one-halves lying around

  • @rakib567
    @rakib567 12 ปีที่แล้ว

    Garfield the cat?

  • @danieltambunan5409
    @danieltambunan5409 7 ปีที่แล้ว

    Oh i know

  • @TheArtOfLivingHappy
    @TheArtOfLivingHappy 12 ปีที่แล้ว

    this is actually the easiest of the three proofs ..... pretty interesting

  • @klesstwo
    @klesstwo 12 ปีที่แล้ว

    he's using a pen with a tablet :)

  • @philz96
    @philz96 12 ปีที่แล้ว

    he´s using a pen tablet

  • @RealisticCookingIRL
    @RealisticCookingIRL 12 ปีที่แล้ว

    Does he like lasagna?

  • @DrEnginerd1
    @DrEnginerd1 12 ปีที่แล้ว

    this makes me realize that we arent 1/10 th the man these guys were, cut from a different cloth i guess. kind of sad really