Can you find the length X? | (Rectangles) |

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  • Опубликовано: 28 дек 2024

Комментарии • 66

  • @yalchingedikgedik8007
    @yalchingedikgedik8007 4 месяца назад +1

    Thanks Sir
    That’s very useful and enjoyable
    We are very interested from the exercises
    ❤❤❤❤❤❤

    • @PreMath
      @PreMath  4 месяца назад

      So nice of you, dear❤️
      You are very welcome!
      Thanks for the feedback ❤️

  • @quigonkenny
    @quigonkenny 5 месяцев назад +10

    I was able to eyeball 12 as the correct answer fairly quickly, but it was nice to see how it was proven.

    • @Micboss1000
      @Micboss1000 5 месяцев назад

      It's kind of a shame that you can eyeball the answer here, makes the math feel redundant.

    • @PreMath
      @PreMath  4 месяца назад +1

      Excellent!
      Thanks for the feedback ❤️

    • @BKNeifert
      @BKNeifert 4 месяца назад

      @@Micboss1000 No, because you get to understand the logic on a deeper level, when you already understand the answer. That's how math gets framed, is by knowing the answer on something simple, and then working logic to construct a ratio for all other numbers to conform to. It's beautiful. But generally, you look at the simpler shapes, and construct a ratio through it, that will inherently get the answer on more difficult problems. You have to understand it fully in its simpler iterations, before you can use it for more complex ones.

    • @sunandasengupta8113
      @sunandasengupta8113 4 месяца назад +1

      Ya. It was easy to calculate 12 . No need for such elaborate process.

    • @BKNeifert
      @BKNeifert 4 месяца назад

      @@sunandasengupta8113 You don't understand? You sometimes need easy calculated things to understand why and how the logic works. He did that deliberately. Like look over the whole thing, and see the nuances of the calculations. How everything, even in complicated form, fits together perfectly.

  • @timeonly1401
    @timeonly1401 5 месяцев назад +3

    @ 8:20 Once you found that y=3, you can get the other side of the green rectangle by dividing y=3 into the area (27) and get 27/3 = 9... WITHOUT plugging y=3 into that ugly expression! Fun problem.

  • @alster724
    @alster724 4 месяца назад

    Easy and useful

  • @devondevon4366
    @devondevon4366 4 месяца назад

    0:44 12
    The width of the blue = 4 (20/5)
    Since the area of the pink =8, let's ASSUME THAT ITS WIDTH = 2 (or half the width of the blue, just by observation it is reasonable to make this assumption since 8 is so small compared to the other areas),
    then 'slice off' 2* 5 of the blue, or area of 10, leaving 10.
    This would leave a rectangle with dimensions x by 5 and a total area of 60 [ 10 (the remaining blue), 27+ 8 + 15).
    Hence, x = 12 (60/5).
    Let's check to see if my assumption was correct:
    If the width of the pink = 2, then the width of the green =3 (given that the length of the yellow =5, hence, the width
    of the yellow =3)
    Therefore, the length of the green is 9 (27/3), and the width of the yellow is 3 (x-9 or 12-9). So far, it has worked out for the green and yellow.
    Also if the length of the green = 9, and the length of the blue =5 (given), then the length of the pink= 4 ( and 4*2 =8, recall
    the assumption was that the width of the pink=2
    Hence, x = 12,

  • @himo3485
    @himo3485 5 месяцев назад +2

    20/5=4 15/5=3
    (x-3)y=27 (x-8)(5-y)=8 x-3=27/y
    (27/y-5)(5-y)=8 135/y-27-25+5y=8 135/y-60+5y=0
    5y²-60y+135=0 y²-12y+27=0 (y-3)(y-9)=0 y=9 is rejected , thus y=3
    (x-3)*3=27 x-3=9 x=12

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @santiagoarosam430
    @santiagoarosam430 4 месяца назад +1

    8=b*(8/b)→ 27=(5+b)[5-(8/b)]→ b=4→ X=(5+4)+(15/5)=9+3=12 ud.
    Buen rompecabezas. Gracias y un saludo cordial.

  • @Tmwyl
    @Tmwyl 4 месяца назад +1

    I got this one!

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @Nothingx303
    @Nothingx303 5 месяцев назад +2

    0:10 blue ,pink and yellow pre math is in my pillow 😊

    • @PreMath
      @PreMath  4 месяца назад

      😀
      Thanks for the feedback ❤️

  • @santokhsidhuatla7045
    @santokhsidhuatla7045 4 месяца назад

    X= 12
    20=5x4=20
    8=4x2=8
    15=3x5=15
    27=27/5-2=9x3=27
    X=9+3=12

  • @richardassal7788
    @richardassal7788 4 месяца назад

    15/5 = 3
    4 x 2 = 8
    3 + 4 + 5 = 12

  • @mracjesstark3468
    @mracjesstark3468 4 месяца назад

    just by looking at it i had it 12. but its good to know the equation process.

  • @murphygreen8484
    @murphygreen8484 4 месяца назад +1

    I got one!

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @michaelkouzmin281
    @michaelkouzmin281 5 месяцев назад +1

    Just another solution:
    W - width; H - height;
    W_yellow = 15/5=3;
    W_green = x - W_yellow = x - 3;
    H_green = 27/W_green = 27/(x-3);
    W_red = W_green - W_blue = (x-3) - 5 = x-8;
    H_red = 8/W_red = 8/(x-8);
    H_yellow = H_green + H_red = 27/(x-3) + 8/(x-8) = 5;
    2 roots: x1 = 12 (accepted); x2 = 6 (rejected as x>8 at least)))
    x= 12.

    • @PreMath
      @PreMath  4 месяца назад

      Thanks for sharing ❤️

  • @ramnagarajan1306
    @ramnagarajan1306 4 месяца назад

    Extend the pink rectangle's into the blue rectangle to split it into two parts. Call the bottom area 5a.
    Total area of the bigger rectangle formed by this is: 27+15+8+5a = 50+5a. Since the height is 5, the length x is (10+a)
    That length can also be expressed as: 5 + (8/a) + 3 = 8 + (8/a)
    So, 10 + a = 8 + 8/a
    Solve to get a = 2
    So, x = 10+a = 12

  • @lilpapi4399
    @lilpapi4399 4 месяца назад

    Blue top side = 5
    Yellow top side = 3 since area 15 and side of 5
    Pink top = 4 since top is longer than side and area is 8, so it has to be 4 x 2 rectangle
    So yeah x = 12

  • @marcgriselhubert3915
    @marcgriselhubert3915 5 месяцев назад +1

    I am always surprised to see how you solve 2nd degree equations.

    • @PreMath
      @PreMath  4 месяца назад

      😀
      Thanks for the feedback ❤️

  • @singaporecambridgeolevelsm8069
    @singaporecambridgeolevelsm8069 4 месяца назад

    Noticed the light blue rectangle is redundant. That shows there's another way to do it . But the solution on the clip is good if it didn't even have to use anything linked to the blue triangle

  • @wackojacko3962
    @wackojacko3962 5 месяцев назад +1

    I go too Great Lengths to achieve something and sometimes do extreme things to achieve it! ...so, @ 7:50 I'm tweekin cuz sometimes I am coherent and other times noncoherent scatter brained and know that neutrons have positive or negative lengths. ...well, I mean scattered lengths that is. 🙂

    • @PreMath
      @PreMath  4 месяца назад +1

      😀
      Thanks for the feedback ❤️

  • @lasalleman6792
    @lasalleman6792 4 месяца назад

    Or 1/2 the blue square, plus the other rectangles = 60. Divide by 5, and guess what? x = 12 Yeah, I know. I know. They want to see if you can set up the quadratic. But, this is so much faster.

  • @Abdullah-ok1mw
    @Abdullah-ok1mw 4 месяца назад

    I can also find x from this 8/(x-8)+27/(x-3)=5
    Wich 5 is right side of figure, x-8 is over side of S=8 figure, x-3 is over side of S=27. x=6 and 12. 6 is not suitable. Answer is x=12.

  • @MrPaulc222
    @MrPaulc222 5 месяцев назад

    In case it's needed, call the vertical y, as in graphs.
    The x direction of yellow is 3, so x>8
    The y direction of blue is 4
    The x direction of grey is a
    x = 8+a
    Visually, grey looks like 4 by 2, so work with that initially.
    Test x=12
    Green is 9 by 3
    Yellow is 3 by 5
    Grey is 4 by 2
    Blue is 5 by 4
    Don't knock the method: science has made assumptions for generations and then proved them later :)

    • @PreMath
      @PreMath  4 месяца назад

      Thanks for the feedback ❤️

  • @unknownidentity2846
    @unknownidentity2846 5 месяцев назад +1

    Let's find x:
    .
    ..
    ...
    ....
    .....
    Let's use the labels x and y for the horizontal and vertical side lengths of the rectangles, respectively. Then we obtain:
    x(b) = 5 ; y(b) = A(b)/x(b) = 20/5 = 4
    y(y) = 5 ; x(y) = A(y)/y(y) = 15/5 = 3
    x(b) + x(p) = x(g)
    y(g) + y(p) = y(y)
    x(p)*y(p) = A(p)
    x(g)*y(g) = A(g)
    5 + x(p) = x(g)
    y(g) + y(p) = 5
    x(p)*y(p) = 8
    x(g)*y(g) = 27
    x(p)*y(p) = 8
    (5 + x(p))*(5 − y(p)) = 27
    x(p)*y(p) = 8
    25 − 5*y(p) + 5*x(p) − x(p)*y(p) = 27
    25 − 5*y(p) + 5*x(p) − 8 = 27
    5*x(p) − 5*y(p) = 10
    x(p) − y(p) = 2
    x(p)*y(p) = 8
    x(p) − y(p) = 2
    (2 + y(p))*y(p) = 8
    2*y(p) + y²(p) = 8
    2*y(p) + y²(p) − 8 = 0
    y(p) = −1 ± √[(−1)² + 8] = −1 ± √(1 + 8) = −1 ± √9 = −1 ± 3
    Since y(p)>0, the only useful solution is:
    y(p) = −1 + 3 = 2
    x(p) = A(p)/y(p) = 8/4 = 2
    y(g) = 5 − y(p) = 5 − 2 = 3
    x(g) = A(g)/y(g) = 27/3 = 9
    Now we are to calculate the value of x:
    x = x(g) + x(y) = 9 + 3 = 12
    Best regards from Germany

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @SidneiMV
    @SidneiMV 4 месяца назад

    ab = 8 => a = 8/b
    x = 8 + a => x = 8 + 8/b
    27 = (x - 3)(5 - b)
    27 = 5x - bx - 15 + 3b
    42 = 5x + 3b - bx
    x = 8 + 8/b => bx = 8b + 8
    42 = 5x + 3b - (8b + 8)
    50 = 5x - 5b => b = x - 10
    x = 8 + 8/b = 8 + 8/(x - 10)
    (x - 8)(x - 10) = 8
    x² - 18x + 72 = 0
    (x - 6)(x - 12) = 0
    b = x - 10 => x > 10 => *x = 12*

    • @PreMath
      @PreMath  4 месяца назад +1

      Thanks for sharing ❤️

    • @SidneiMV
      @SidneiMV 4 месяца назад

      another way [ but something similar ]
      5x = 27 + 15 + 8 + 5h
      (where bh = 8)
      5x = 50 + 5h => h = x - 10
      (x - 3)(5 - h) = 27
      5x - xh - 15 + 3h = 27
      xh - 3h - 5x + 42 = 0
      x(x - 10) - 3(x - 10) - 5x + 42 = 0
      x² - 10x - 3x + 30 - 5x + 42 = 0
      x² - 18x + 72 = 0
      (x - 6)(x - 12) = 0
      h = x - 10 > 0 => x > 10 => *x = 12*

  • @adhiraj073
    @adhiraj073 5 месяцев назад +2

    first?, why does it even mattter

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for the feedback ❤️

    • @sabbur15
      @sabbur15 4 месяца назад

      Some people will never use math. Others will. Engineers need to be able to figure out stuff like this all the time.

  • @johnbrennan3372
    @johnbrennan3372 4 месяца назад

    Length of green rectangle is 27/(x-3). Length of pink rectangle. Is 8/(x-8). So 5=8/(x-8)+27/x-3 That gives a quadratic equation where x=8 and x=12, so x=12 since it can’t be = 8.

  • @adamrussell658
    @adamrussell658 3 месяца назад

    Just looking at the diagram it looks like pink is 2x4. Yellow is 5x3 so X is 3+4+5=12. And since the numbers all work out with no contradictions our original assumption for pink is correct and our answer is correct.

  • @prossvay8744
    @prossvay8744 5 месяцев назад +1

    x=12 units

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @Pixel_Runner
    @Pixel_Runner 4 месяца назад

    Did anyone else just work out 3 (for the bottom right rectangle). Then look at the bottom length rectangle and know that it must be 3*9.
    So it must have been 12. Much easier and quicker!

  • @frankmutuma3360
    @frankmutuma3360 4 месяца назад

    Could solve for X directly by using the rectangle of area 8 and obtaining x2 - 18x + 72 = 0.

  • @DorothyMantoothIsASaint
    @DorothyMantoothIsASaint 4 месяца назад

    H_yel = 6
    W_blue = 4, W_yel = 3, W_gr = x -3, W_red = x - 8
    H_red = 8/(x-8), x > 8
    H_gr = H_yel - H_red = 5 - 8(x-8)
    A_gr = W_gr * H_gr
    27 = (x-3) [5 - 8(x-8)]
    27 = 5x - 15 - [8x/(x-8)] + 24/(x-8)
    42 = [5x(x-8) - 8x + 24 ] / (x-8)
    42(x-8) = 5x^2 -40x -8x +24
    42x - 336 = 5x^2 - 48x + 24
    5x^2 - 90x + 360 = 0
    x^2 - 18x + 72 = 0
    (x -6)(x-12) = 0
    x> 8 so x = 12

    • @PreMath
      @PreMath  4 месяца назад

      Thanks for sharing ❤️

  • @mathswithtvs2682
    @mathswithtvs2682 5 месяцев назад

    12

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @johnny3433
    @johnny3433 4 месяца назад

    1 min for me

  • @Birol731
    @Birol731 5 месяцев назад +1

    My way of solution ▶
    20= 5*t
    t= 4
    15= 5*u
    u= 3
    a+b= 5
    b+c= 4

    a+b= 5
    -b-c= -4
    a-c= 1
    a= c+1
    we can write a= c+1
    b*d= 8......................(I)
    a(5+d)= 27..............(II)
    a= c+1

    (c+1)(5+d)= 27.......(III)
    c+1+b= 5
    b+c= 4
    b= 4-c
    if we put this in the equation (I) above:
    b*d= 8
    (4-c)*d= 8
    d= 8/(4-c)

    (c+1)*(5+d)= 27.......(III)
    if we put d= 8/(4-c) we get:
    (c+1)*[5+ 8/(4-c)] = 27
    (c+1)*(20-5c+8)/(4-c)= 27
    (c+1)(28-5c)= 27(4-c)
    28c-5c²+28-5c= 108-27c
    5c²-27c+108-28-23c=0
    5c²-50c+80= 0
    c²-10c+16=0
    Δ= 100-4*1*16
    Δ= 36
    √Δ= 6
    c₁= (10+6)/2
    c₁= 8
    c₂= (10-6)/2
    c₂= 2
    if c= 8
    b= 4-c would be negative❗

    c= 2
    b= 4-c
    b= 4-2
    b= 2
    d= 8/(4-c)
    d= 8/(4-2)
    d= 8/2
    d= 4
    x= 5+d+u
    x= 5+4+3
    x= 12 length units

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @asbjrnlarsen4033
    @asbjrnlarsen4033 4 месяца назад

    12 blir svaret

  • @timmcguire2869
    @timmcguire2869 4 месяца назад

    I always estimate a ballpark for the answer before I start - just to make sure my answer at the end makes sense. In this case I said x looks like it should be 11, 12, or 13ish. In my head 6 plugged the 12 in for x and bingo, saw it worked without picking up the pencil. Of course, that doesn't always work out that way :-)

  • @LuisdeBritoCamacho
    @LuisdeBritoCamacho 4 месяца назад +1

    STEP-BY-STEP RESOLUTION PROPOSAL :
    Let's check these Solutions :
    01) Sum of All Areas = 70
    02) 20 / 5 = 4
    03) 15 / 5 = 3
    04) 27 = 3 * 9 (?)
    05) 8 = 4 * 2 (?)
    06) Left Side = 4 + 3 (?)
    07) The only possible solution herein is x = 9 + 3 = 12

    • @PreMath
      @PreMath  4 месяца назад

      Excellent!
      Thanks for sharing ❤️

  • @samswift4921
    @samswift4921 4 месяца назад

    12

  • @Xyz-sd7ub
    @Xyz-sd7ub 4 месяца назад

    12