Area of Blue Triangle

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  • เผยแพร่เมื่อ 10 ม.ค. 2024
  • I hope you guys like this one!
    Let me know if you see an easier way to solve it!
    Any requests for other things I should work on?
    Thank you!

ความคิดเห็น • 117

  • @oblivion4753
    @oblivion4753 6 หลายเดือนก่อน +177

    instead of using the law of cosines, side c that is being solved for can be found more quickly with the pythagorean theorem. its touching the bottom of the small square and the top left of the medium square so its length is equal to the square root of 2^2 + 6^2

    • @aps5355
      @aps5355 6 หลายเดือนก่อน +5

      explain it better pls

    • @joevano
      @joevano 6 หลายเดือนก่อน +3

      Where is the right triangle you are using the Pythagorean theorem on?

    • @rudozawa
      @rudozawa 6 หลายเดือนก่อน +20

      @@joevano You can draw a vertical line from the lowest point of the diagonal square to the midpoint of the top edge of the first square. This forms a right triangle with known side lengths of 2 and 6.

    • @Saryn776
      @Saryn776 6 หลายเดือนก่อน

      ​@@joevano divide the small square into pieces.

    • @joevano
      @joevano 6 หลายเดือนก่อน

      @@rudozawanot seeing it at all… and you do know there are 2 diagonal squares…

  • @lilywilliams2907
    @lilywilliams2907 6 หลายเดือนก่อน +33

    I’m proud of myself! I did it a little differently (not using law of cosines) and got the right answer all in my head. I’ve been enjoying your videos lately 😁

    • @jonathanlegendre279
      @jonathanlegendre279 5 หลายเดือนก่อน

      Did you drop a vertical line from the base of the 4x4 square to the bottom point of the rhombus and use Pythagorean theorem again to get that side length of the largest square? That's what I did.

    • @chinanumberone7723
      @chinanumberone7723 5 หลายเดือนก่อน +1

      Someone’s happy. Only comment on this channel, all because Lily Williams is happy 🙄
      Seems like we have a seIfish person folks

    • @iqwit
      @iqwit 5 หลายเดือนก่อน

      ​@@chinanumberone7723you're just mad that you can't solve it yourself

    • @lilywilliams2907
      @lilywilliams2907 5 หลายเดือนก่อน

      @@chinanumberone7723 hey I don't know if you had a bad day or something, but being happy and sharing that happiness isn't selfish. I'm sorry that I triggered you. At the same time, I never said anything about people being allowed to comment so I'm confused, would you mind clarifying?

    • @lilywilliams2907
      @lilywilliams2907 5 หลายเดือนก่อน

      @@jonathanlegendre279 Yeah! I thought that that method would be easier for me and it really does seem so much simpler. I'm glad someone else saw that method too :)

  • @jeffhearn3658
    @jeffhearn3658 6 หลายเดือนก่อน +10

    Andy, congrats on the 100K subscribers…..”How exciting!”
    Love the vids, keep up the great work.

  • @PetDogScout
    @PetDogScout 6 หลายเดือนก่อน +1

    100k subscribers for my favorite youtuber!!! Congratulations Andy. How exciting.

  • @manofmartin
    @manofmartin 29 วันที่ผ่านมา

    Im not sure what i like more, the solving of the equation or how exciting it is!

  • @yurio4804
    @yurio4804 6 หลายเดือนก่อน +8

    I love your videos. For fun or studies they are the best ni doubt, just like you. Keep being amazing.

  • @ziaal243
    @ziaal243 6 หลายเดือนก่อน +1

    Really like your channel. Thanks for the content

  • @guyonabike91
    @guyonabike91 6 หลายเดือนก่อน +5

    Solved with geometry:
    Use a^2 + b^2 = c^2 to calculate the smallest square side length as sqrt8.
    Noting that we have 3 squares in the diagram, the diagonal across the medium square can be completed up to its top left corner, and be of total length 2sqrt8.
    We now have an identical triangle to the blue one, with short side length sqrt8 and perpendicular medium side length 2sqrt8.
    Area = 1/2 x base x height
    A = 1/2 x 2sqrt8 x sqrt8
    1/2 x 2 cancels, so A = sqrt8 squared
    A = 8 cm^2

    • @bectionary
      @bectionary 6 หลายเดือนก่อน

      Which is the hypotenuse in this triangle you’re constructing?

    • @guyonabike91
      @guyonabike91 6 หลายเดือนก่อน +1

      @@bectionary right hand side of the largest square.

  • @Marzy07
    @Marzy07 6 หลายเดือนก่อน +5

    This is the first video I’ve ever attempted one of these questions and I happened to almost get it correct

  • @edoardobonel5845
    @edoardobonel5845 6 หลายเดือนก่อน +3

    Congrats on 100k Andy!

    • @AndyMath
      @AndyMath  6 หลายเดือนก่อน +3

      Thank you! It makes me happy you were looking at the counts! It happened last night.

  • @thiagomotta777
    @thiagomotta777 5 หลายเดือนก่อน

    i would have never thought that one of my favorite yt channels would be a guy doing maths

  • @stixoimatizontas
    @stixoimatizontas 6 หลายเดือนก่อน +2

    Question: why does he check if the smallest square is actually a square, when all of the sides are equal? Did I miss something?
    Edit: I just realised why he called it a rhombus. 4 equal sides doesn't necessarily mean square.

  • @Ruija27
    @Ruija27 6 หลายเดือนก่อน +3

    I just used the Pythagorean theorem a bunch. Everything about sines and cosines and such has escaped my mind since school.
    The diagonal of the medium square is 4*sqrt(2), half of that is the side length of the small square (whose diagonal is 4). So the short side of the blue triangle is 2*sqrt(2).
    With parts of these squares, the side of the large square forms the hypotenuse of a right triangle with sides 2 and 6. The large square's side length is 2*sqrt(10).
    Then you get the missing side length of the blue triangle via Pythagoras again, that's sqrt(32). Half base times height [½ * sqrt(32) * 2*sqrt(2)] and you get an area of 8 cm^2.

  • @danpliska924
    @danpliska924 6 หลายเดือนก่อน

    congrats on the 100k subscribers. it has been a long journey. keep making great videos.

    • @AndyMath
      @AndyMath  6 หลายเดือนก่อน

      Thank you very much!

  • @ItsDoZy
    @ItsDoZy 6 หลายเดือนก่อน +1

    Congrats on 100k subs :D !

    • @AndyMath
      @AndyMath  6 หลายเดือนก่อน

      Thank you so much! 😀 I can't believe it.

  • @pantumaka89
    @pantumaka89 6 หลายเดือนก่อน

    i did it by just figuring out the side of the rhombus, then making a right triangle with the shortest side of the blue triangle and half of the side of the big square to figure out that half, multiplied it by two, and did pythagorean on the blue triangle. in my opinion the way i solved it is a little better since it doesn't make use of the law of cosines and thus angles as a way of calculating sides but yours is still nice

  • @zg0493
    @zg0493 หลายเดือนก่อน

    A generalized solution: Let a=side of the smallest square; the area of the blue triangle is always a^2.
    Proof: Let ABC the blue right triangle, A=90°, AC=a. Let D the upper right corner of the medium square. We can easily prove that B, A, D are collinear, thus BCD is an isoceles triangle (BC=CD=CE, E is the upper left corner of the medium square), and AB=AD= 2a.

  • @KanNgnKanKurt
    @KanNgnKanKurt 6 หลายเดือนก่อน +1

    Nice one! :)

  • @bloodgoat
    @bloodgoat 6 หลายเดือนก่อน +2

    Simple, clean math

  • @olivermelo333
    @olivermelo333 2 หลายเดือนก่อน

    Given that side | is 4cm, I'd solve it like this:
    Alegation 1: side || = (side | * _/2) / 2, then side || = 2_/2 cm [equation of the diagonal of a square, divided by 2, as side || is half the diagonal of square with side | ]
    Alegation 2: the half of side | equals to 2 cm
    Alegation 3: now on the scalene triangle side |, side ||, side |||, we can extend the straight line side | down; also, we can create a new line from side III's bottom frontier point; and, finally, we make them intersect in a way they become perpendicular to each other. Thus, we have a right-angled triangle.
    Alegation 4: isosceles triangle side ||, side ||, side | has a height that half of side | (that is, 2 cm).
    Alegation 5: there are two equal isosceles triangles side ||, side ||, side |, thus everything appliable to one also applies to the other.
    Alegation 6: clearly, the right-angled triangle's side created by extending the scalene triangle's side | is the sum between the height of the isosceles triangle found in Aleg. 4 and the length of side |; that is, 2 + 4 = 6.
    Alegation 7: also, clearly the straight line created from side III's bottom frontier point on Aleg. 3, which is side of the right-angled triangle, has a length of 2 cm.
    Alegation 8: being the triangle created in Aleg. 3 right-angled, and knowing the side of the two catheti, and knowing side ||| is the hypotenuse, we can apply Pythagoras' Theorem: 6^2 + 2^2 = side ||| ^ 2; thus side ||| = 2_/10
    Alegation 9: having now side || and side |||, we can calculate the one cathetus of the blue right-angled triangle which length we don't know, by using Pythagoras' Theorem once more: (2_/2) ^ 2 + cathetus ^ 2 = (2_/10) ^ 2; thus, cathetus = 4_/2
    Alegation 10: now, to calculate the area, we just need to multiply the catheti and divide by 2, as one of the catheti is already the triangle's height; thus, the area of the blue triangle is: (2_/2) x (4_/2) / 2 = 8 cm2
    Q.E.D.

  • @noobtyoub_735
    @noobtyoub_735 6 หลายเดือนก่อน +3

    I like this man

  • @rupom_1670
    @rupom_1670 6 หลายเดือนก่อน +1

    Got everything first try except the theta angle in the laws of cosine part
    Although i understood it after your explanation

  • @anytorp
    @anytorp 6 หลายเดือนก่อน

    amazing video as always

  • @mawuliatsrefi9715
    @mawuliatsrefi9715 6 หลายเดือนก่อน +5

    How exciting indeed🤗

  • @CharlesShorts
    @CharlesShorts 6 หลายเดือนก่อน +1

    Congratulations on 100K 🥳🥳

    • @AndyMath
      @AndyMath  6 หลายเดือนก่อน +1

      Thank you!!

  • @enzomunoz2519
    @enzomunoz2519 5 หลายเดือนก่อน

    Amazing 🎉

  • @OptimusPhillip
    @OptimusPhillip 5 หลายเดือนก่อน

    Huh, I had modeled the triple-ticked line segment as a vector, basing its horizontal and vertical components off the dimensions of the squares it touches the corners of. Got the same solution, though.

  • @JacopoMarengo
    @JacopoMarengo 5 หลายเดือนก่อน

    Faster solution without trigonometry:
    - diagonal of big square (z) = 2c^2
    - connect (a) to the middle of the medium square and have a new side called (a + b), and generate a new rectangular triangle made of (z), (a+b) and (b)
    - z^2 = 2c^2
    - z^2 = (a+b)^2 + b^2
    - c^2 = a^2 + b^2
    It gives at the end that a^2 = 32

  • @ScubaBob-zm6wo
    @ScubaBob-zm6wo 2 หลายเดือนก่อน

    I think I can give a creative solution
    Say the blue triangle with corners ABC, Boeing AB the side of the small square (you solved as x), and AC the other catheto (lets name it y), and BC the hypotenuse (lets name it z) equal to the side of the large square
    The area of the blue triangle would be 1/2(xy)
    Lets name the rightmost common point between the medium and small sqare D, and the common point between the medium and large square E
    You'll now have 2 congruent right triangles, ABC and DBE (AB=BD=x, BC=BE=z, therefore AC=DE=y)
    Now, you'll have another right triangle ADE, with AD=AE=4, where we can also conclude that DE=2x
    So, the final blue triangle area is going to be 2x×x/2=x²=8

  • @jdmjesus6103
    @jdmjesus6103 5 หลายเดือนก่อน

    I used trig and got slightly less than 8 due to rounding errors, it was easier, but it makes sense to do it your way and get an exact answer.

  • @funwithtommyandmore
    @funwithtommyandmore 6 หลายเดือนก่อน +1

    Congratulations on 100k

    • @AndyMath
      @AndyMath  6 หลายเดือนก่อน +1

      Thank you!!

  • @user-oe6hv6gb9h
    @user-oe6hv6gb9h 6 หลายเดือนก่อน

    Which software did you used to make these exciting videos.😊

  • @n_9_70
    @n_9_70 6 หลายเดือนก่อน

    trig is my favorite subsection of math

  • @themathhatter5290
    @themathhatter5290 6 หลายเดือนก่อน +3

    This also implies that if the square with the original defined side length instead has side length x, the blue triangle derived will have area equal to half the square's area, or (x^2)/2.

    • @carlosmp2043
      @carlosmp2043 6 หลายเดือนก่อน

      How can you generalise that so confidently lol

    • @themathhatter5290
      @themathhatter5290 6 หลายเดือนก่อน

      @@carlosmp2043 Because if we scale it up or down by any multiple k, the areas will remain in proportion. The original square has area 4*4=16 units squares, and we worked out the blue triangle has area 8 units square. Thus, it will always be that the ration of triangular area to square area will be 8/18=1/2

    • @carlosmp2043
      @carlosmp2043 6 หลายเดือนก่อน

      @@themathhatter5290 it should make sense intuitively I agree since everything depends on the original square, but it's still bold to make the assumption that it will always be half, since it could follow some other ratio (Could be for example 4+(x^2)/4 or some other random stuff that would work for x=4 specifically but not other values of x). I feel like a bit of more formal proof would be needed to make that statement but Im not sure

    • @themathhatter5290
      @themathhatter5290 6 หลายเดือนก่อน

      @@carlosmp2043 If you would like to do the whole proof again but with a side length "Z" instead of four, go ahead! It'll be very rewarding, I assure you.

    • @carlosmp2043
      @carlosmp2043 6 หลายเดือนก่อน

      @@themathhatter5290 I believe ya, but trying it with 2, 10 or even a million variables in not sufficient mathematical proof if we play by the rules lol, more empirical proof is needed. Guess I'm just nitpicking here tho, I do agree that it should make sense.

  • @myonice.3097
    @myonice.3097 6 หลายเดือนก่อน +1

    i have alternative solution instead using cosine law, i only use pytaghorean.
    We see there is triangle in 1:10, we can use that to find half length of the sides of biggest square
    =sqrt( sqrt(8) + sqrt(8)/2) = sqrt(10)
    So the full length is 2*sqrt(10) = sqrt(40)
    Then continue to this 2:49

    • @Gaxi2
      @Gaxi2 6 หลายเดือนก่อน

      Explain clearly

    • @Sanji-kun_69
      @Sanji-kun_69 4 หลายเดือนก่อน

      Agreed

  • @maxwelljennings4178
    @maxwelljennings4178 6 หลายเดือนก่อน

    (note: I'm labelling the squares based on the number of lines that cross to denote equivalent disntances)
    buffer
    buffer
    buffer? I hardly know 'er
    based on the length of square 1, we can find the side length of square 2 using pythag's theorum (a²+b² = 16, a = b, 2a² = 16, a² = 8, a = √8).
    from that, we can find the right triangle that would define the length of square 3, as square 2 is rotated 45° compared to square 1. find the (invisible) legs of the isoceles/right triangle using the same method as above (2c² = 8, c² = 4, c = 2)
    the right triangle described is a 4+2 by 2 triangle (that is, 6 by 2) and we can PT this. we get d = √40.
    we now have the hypotenus (d) and one leg (a) of the blue triangle. PT but weird. 40 - 8 = 32, e = √32
    (√32 * √8)/2 -> (√256)/2 -> 16/2
    thus
    area = 8

  • @themihanoid5020
    @themihanoid5020 6 หลายเดือนก่อน

    Strictly speaking, you have to explain the transition from the right angle in the blue triangle, to the right angle in the "smallest rombus", because even tho it looks that way, the fact the bigger cathetus aligns with the side of the smaller rombus to form a straight line has to be proven

  • @fartenko
    @fartenko 6 หลายเดือนก่อน +1

    How exciting

  • @Y-LAT
    @Y-LAT 6 หลายเดือนก่อน

    Man, I can't unsee it being 3d

  • @user-uc2qy1ff2z
    @user-uc2qy1ff2z 3 หลายเดือนก่อน

    Side of medium square is b=4.
    1. Side on small square is a=b sin(45)=2sqrt(2)
    2. Mirror small square along right side of triangle.
    3. Prove, that new triangle is equal to original one.
    It's a right angled triangle with hypothenuse, equal to side of big square. And side equal to small square.
    4. Since one side is a and other is 2a, S=2a²/2= a²=8
    Completely no reason for equations.

  • @bene2451
    @bene2451 6 หลายเดือนก่อน

    I think Mr.Math kinda overcomplicated it. smallest square side = 4/sqrt(2) diagonal of medium square= 8/sqrt(2) biggest square side= sqrt((8/sqrt(2))^2+(4/sqrt(2))^2) hyp. of blue triangle= biggest square side smallest side of blue triangle= smallest square side then you can easily solve for third side and area of the blue triangle without law of cosines. Yes, I know, I didn't provide proof that the diagonal of the medium square is equal to double the length of the little square but I can guarantee that it is, work it out on paper for yourself.

  • @Armstrong1781
    @Armstrong1781 6 หลายเดือนก่อน

    thank you
    good math

  • @sundown456brick
    @sundown456brick 6 หลายเดือนก่อน

    i got scared with the thumb, at least on my side the measure is cut out of the image
    clicked to see how you would solve for the area of something without units in under 4min lol
    amazing video

  • @tedlasso2887
    @tedlasso2887 6 หลายเดือนก่อน

    Wow Really How Exciting 🎉

  • @xplodingmojo2087
    @xplodingmojo2087 6 หลายเดือนก่อน

    The law of cosines… man that brings me back to highschool…

  • @artemirrlazaris7406
    @artemirrlazaris7406 6 หลายเดือนก่อน

    Ever thought of doing a math compile of rules to functions and thought process behind it... since you added brackets wit ha divisional sign but it was fraction so you didn't multiply it and some people are ocnfused why everything in teh bracket is not computed... the clarity or lack of it in math grammar is sometimes a thing ,but it would be an interesting rule set... and maybe peopel might learn something...
    Other methods for quadratic equations, to solve such as factoring, binary method I thought was my favourtie way for a x=0 equation.. lol Ther are so amny like bingo box thing.. and many others. lol nothing really teaches... actual reason behind it but its a fucnitonal work rather than teh logistics of pattern systems in question whihc ould make most humans a geunius that besides the point ,the ways of the math.. to solve complex questions... would be interesting. Helpful sets to know... common pairs and bonds.. this owuld help a lot of peopel maybe upgrading also... its liek shortcuts.

  • @Simeulf
    @Simeulf 6 หลายเดือนก่อน +1

    Can you make a channel called Andy Meth? Where you solve drug math problems on meth?

  • @roi_halltari
    @roi_halltari 6 หลายเดือนก่อน

    Math is so so so beautiful

  • @JohnTurner313
    @JohnTurner313 6 หลายเดือนก่อน +1

    0:20 Nice solution! Just a note: we already know the shape with diagonal length 4 is a square because 3 of its 4 lines have the double hash marks. That means 3/4 of the sides are the same length making it a square automatically. No need for the right angles.

    • @rudozawa
      @rudozawa 6 หลายเดือนก่อน +6

      Three sides having the same length does not necessarily mean it's a square. A trapezoid could have three identical side lengths with a longer base, as an example. Four identical side lengths could be a rhombus, so we still need to double check to confirm!

    • @dahorn100011
      @dahorn100011 6 หลายเดือนก่อน

      @@rudozawa The diagram is drawn incorrectly. My understanding is the perpendicular line means the side length is the same. The rhombus has 4 sides of equal length,, just the notation for it is crossing with the line of the large square.

  • @kozhambetov
    @kozhambetov 5 หลายเดือนก่อน

    ez. solven in my head

  • @utsavjha1791
    @utsavjha1791 6 หลายเดือนก่อน

    Bro we can do the math without law of cosines. We can prove that the side of triangle of the" 4cm "square that it is the half of the square's diagonal and join the corner with the side of the triangle with an imaginary line. This forms a right angled triangle and we can find the value of the side of the big square.

  • @YeeaauaruJf
    @YeeaauaruJf 6 หลายเดือนก่อน

    100k ❤🎉

  • @robin.elflein
    @robin.elflein 6 หลายเดือนก่อน

    Can’t you just say that the side that is sqrt(32) is double the length of sqrt(8) so 2*sqrt(8) which is sqrt(32)? Should be obvious if you flip the blue triangle along its shortest side. Sou you don’t have to calculate the sqrt(40)?

    • @myonice.3097
      @myonice.3097 6 หลายเดือนก่อน +2

      i think there's not enough proof to do that

  • @razanmuhammadiksan7225
    @razanmuhammadiksan7225 4 หลายเดือนก่อน

    chill bruv my girl is on this app

  • @varsha9075
    @varsha9075 6 หลายเดือนก่อน

    Instead of using law of cosines we can jst construct a line joining top of the kite like square to the left corner of the square of side 4 cm
    And then we can find the side of the biggest square...
    Here one side is known and we can find the second one by Pythagorean theorem and then we can find its hypotenuse which the side of the biggest square by Pythagorean theorem....🧠 :⁠-⁠)

  • @not_estains
    @not_estains 6 หลายเดือนก่อน

    i hope im correct with 2.83 ima watch the video now
    edit 4 seconds in and i realized i forgor to square the 4, 5.66
    edit 2, im stupid and none of my answers are correct because of a non-right triangle

  • @KristianYeager
    @KristianYeager 6 หลายเดือนก่อน +1

    There is absolutely NO reason to use the Law of cosines here

  • @jaysanXD
    @jaysanXD 6 หลายเดือนก่อน

    I bet you can't solve me! My parents said I was the biggest problem...

  • @serk-s
    @serk-s 5 หลายเดือนก่อน

    Hmmm...I have another solution. I will review it. 😃

  • @zekdopa591
    @zekdopa591 6 หลายเดือนก่อน

    I can’t believe i did everything right and then forgot to divide the final area by 2

  • @tomdekler9280
    @tomdekler9280 6 หลายเดือนก่อน

    Law of cosines??? My brother in Christ just draw the III line from the rightmost corner of the blue triangle to the topright corner of the medium square, and extend the II line.
    You now have the blue triangle, but mirrored along the short side. The base is twice as big as the small square and the height is the same, so the surface of the blue triangle is the same as the small square's.

  • @mategede146
    @mategede146 6 หลายเดือนก่อน

    i could actually do this

  • @alexobiz
    @alexobiz 6 หลายเดือนก่อน

    😢😮😮😮😢

  • @ISoldBinLadensViagraOnEbay
    @ISoldBinLadensViagraOnEbay 6 หลายเดือนก่อน

    V

  • @tilekt4248
    @tilekt4248 6 หลายเดือนก่อน +1

    Just put another double-crossed line from the center of the medium square to its upper left corner and boom!

  • @davidurbanik5021
    @davidurbanik5021 6 หลายเดือนก่อน

    I got 8cm^2

    • @davidurbanik5021
      @davidurbanik5021 6 หลายเดือนก่อน

      I used different way to caltulate it:
      1) 4^2=16 -> 16:2=8 V8
      2) V8^2 + 0.5V8^2= 10
      3) 2V10^2 - V8^2= 32
      4) 2V8*V8:2= 8cm^2
      No calculator, no paper🙂

  • @ShivamSharmaIRS
    @ShivamSharmaIRS 3 หลายเดือนก่อน

    th-cam.com/video/6lCwFyE-Nm0/w-d-xo.html This is another way to solve this problem which I really liked. Kudos to this Indian guy!

  • @ragemodegaming7962
    @ragemodegaming7962 6 หลายเดือนก่อน +1

    How dare you trick us into using trig. Disgusting.

  • @yepyepmusic
    @yepyepmusic 6 หลายเดือนก่อน

    Im like 69

  • @GregoryFord98
    @GregoryFord98 6 หลายเดือนก่อน

    How exciting