A Very Nice Geometry Problem | Find the area of the trapezium | 2 Methods

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  • Опубліковано 24 лис 2024

КОМЕНТАРІ • 67

  • @AmirgabYT2185
    @AmirgabYT2185 2 місяці тому +7

    Let's drop two heights from the upper vertexes down to the larger base. They will be h each.
    Let segments we got by dropping heights be a (the left one) and b (the right one) and middle which is equal to the smaller base and that is 10.
    Then we got:
    h²=13²-a²
    On the other hand:
    h²=14²-b²
    So:
    169-a²=196-b².
    And also:
    a+b+10=25
    After few changes, we can make a system:
    b²-a²=27
    a+b=15
    Let's solve it.
    (b-a)(b+a)=27
    a+b=15
    15(b-a)=27
    b-a=1,8
    We got a new easier system:
    b-a=1,8
    a+b=15
    Let's add equations to each other:
    2b=16,8
    b=8,4=42/5
    a=6,6=33/5
    Let's find h:
    h²=196-(42/5)²
    196-1764/25=h²
    3136/25=h²
    h is a height so h>0 => h=56/5=11,2
    S=(10+25)11,2/2=35•5,6=196
    Answer: 196 square units.

  • @srizzio
    @srizzio Місяць тому

    Cool problem. Used different strategy. Created one triangle by taking the left and right sides of the trapezoid. Hence, a triangle with sides 13, 14, and 15. Used Heron's formula to calculate area of triangle. Took that value and calculated height of triangle, which is the height of the trapezoid. I dumped that value into the area formula for a trapezoid. Solution.

  • @kaliprasadguru1921
    @kaliprasadguru1921 27 днів тому +1

    Draw BE parallel to AD. Then EC =15 . Determine area of triangle BEC . Then determine its height . Now determine the area of Trapezium.

  • @murdock5537
    @murdock5537 2 місяці тому +11

    x = √(13^2 - h^2) = 15 - √(14^2 - h^2) → h = 56/5 → area ABCD = 125h
    or: ∆ BPC → CP = 15; BP = 13; BC = 14; BPC = θ → cos⁡(θ) = 33/65 →
    sin⁡(θ) = 56/65 = h/13 → h = 56/5 → area ABCD = 125h

  • @josephkt6830
    @josephkt6830 24 дні тому +1

    Very good illustration.thanks

  • @dhorasokoli47
    @dhorasokoli47 2 місяці тому +1

    In short, it could be solved like this: The height comes from the solution of the equation 13^2-x^2=14^2-(15^2-x^2)^2 because the height is expressed by the Pythagorean theorem in two forms in two right triangles. The solution gives x=6,6. Then apply T.P. in one of the triangles and the height h=11.2 comes out. In the end S=[(25+10)×11,2]÷2= 196cm^2

  • @baselinesweb
    @baselinesweb 2 місяці тому

    I took the long way, but got that answer too. I made a regular trapezoid (13 on both left and right) and then the full right triangle had a base of x for 13 and x+x1 for 14. It was fun.

  • @wes9627
    @wes9627 Місяць тому

    f(h)=√(13^2-h^2)+√(14^2-h^2)-15=0
    f'(h)=-h/√(13^2-h^2)-h/√(14^2-h^2)
    Newton-Raphsin iteration: Start with h=10 and iterate h←h-f(h)/f'(h) until h=11.200...
    The area is then (1/2)(10+25)11.2=196 sq units.

  • @imetroangola17
    @imetroangola17 2 місяці тому +6

    In method 2, it would be more interesting if you had found the area of the parallelogram and, after adding it to the area of the triangle, finally, we would have the area of the trapezoid:
    [ABPD]=h×BP=56/5 × 10=112, Therefore,
    [ABCD]=[ABPD]+[BCP]
    *[ABCD]=84+112=196*

    • @quigonkenny
      @quigonkenny 2 місяці тому

      Seems to me like you're just adding additional unnecessary steps. You use the area of the triangle to get the value of h, but once you have that it's unnecessary to find the area of the parallelogram, since you can use h to directly find the area of the whole trapezoid.

    • @purnajinananandaavadhuta8605
      @purnajinananandaavadhuta8605 2 місяці тому

      We need not find the height in the 2nd method. Area of the parallelogram = 84*10*2/15=112. Total area= 84+112=196

    • @imetroangola17
      @imetroangola17 2 місяці тому +1

      ​@@quigonkennyUnfortunately, you didn't understand what I meant, in the second method it would be more interesting not to use the formula for the area of the trapezoid, as it is easier to find the area of the parallelogram.

    • @imetroangola17
      @imetroangola17 2 місяці тому

      ​@@purnajinananandaavadhuta8605It can be done like this, but for the sake of explanation, the interesting thing is to find the height!

    • @RAG981
      @RAG981 2 місяці тому

      @@quigonkenny Area parallelogram is just 10x56/5 =112, and add to 84. That is much simpler.

  • @santiagoarosam430
    @santiagoarosam430 2 місяці тому

    DC=a+10+(25-10-a)→ 13²-a² =h²= 14²-(15-a)²→ a=33/5→ h²=13²-(33/5)²→ h=56/5→ Área ABCD =[(10+25)/2]*(56/5)=196 ud².
    Gracias y saludos.

  • @kateknowles8055
    @kateknowles8055 Місяць тому

    Let height of trapezium be h. Draw AE and BF both equal to h , so that DEFC is a straight line.
    Area of triangle ADE = 0.5h x DE. Area of triangle BFC = 0.5 h x FC . Area of AEFB (the rectangle) is 10h.
    hxh= 13x13- DExDE= 14x14- FCxFC by Pythagors'theorem in both triangles
    FCxFC -DExDE = 14x14-13x13 = 196-169 =27
    (FC+DE)(FC-DE)=27
    FC+DE+10= 25 so FC-DE = 27/ 15 = 9/5
    FC+DE=15
    FC-DE=9/5 =1.8
    2xFC = (15x5+9)/5
    FC=8.4
    DE= 6.6
    13x13- 6.6x6.6= (13+6.6)(13-6.6)= 19.6 x 6.4= 196 x64/(10x10) = h x h. So h= 14x 8/10 = 112/10 = 11.2
    Area of this trapezium = 11.2 (10 + 4.2 + 3.3) = 11.2 x 17.5 = 2.8 x 70 = 196 square units .

  • @RealQinnMalloryu4
    @RealQinnMalloryu4 2 місяці тому +1

    (13)^2=169 (14)^2=196 {169+196}=365 (10)^2=100 (25)^2=625{100+625}=725 {365+725}=1090/180°ABCD =6 .50ABCD 6.5^10 6.5^2^5 3^2.1^2^1 3^1.2^1 3.2 (ABCD ➖ 3ABCD+2).

  • @alster724
    @alster724 Місяць тому

    Nice use of the Herons on Method 2

  • @adgf1x
    @adgf1x 19 днів тому

    ar=11.2(10+25)/2=112×35/2×10==56×7/2=28×7=196 sq.

  • @adgf1x
    @adgf1x 2 місяці тому +1

    ar.=196sq unit.ans

  • @satrajitghosh8162
    @satrajitghosh8162 2 місяці тому +1

    Draw AE || BC that cuts BC at E
    Area ( Trapezium ABCD)
    / area ( ∆ ADE)
    = ( AB + CD)/DE
    = ( AB + CD) / ( CD - AB)
    = ( 25 + 10)/( 25 - 10)
    = 7/3
    Area ( ∆ ADE) of sides 13, 14, 15
    = √ ( 21 * 8 * 7 * 6) sqr unit
    = 7 * 3 * 4 sqr unit
    = 84 sqr unit
    Area of Trapezium ABCD
    = (7/3) * 84 sqr unit
    = 196 sqr unit
    Corollary : Area of a trapizum with obleque sides a, b and, parallel sides x, y is (x> y)
    ∆ ( a, b, (x - y)) * ( x + y)/( x - y)
    Here ∆ ( a, b, c = (x - y))
    = √ ( s * ( s - a) ( s - b)( s - c))
    s = ( a + b + c)/2

  • @subbaraob8474
    @subbaraob8474 10 днів тому

    Super solution

  • @wasimahmad-t6c
    @wasimahmad-t6c 22 дні тому

    10+25=35÷2=17.5×11.2=196(100%raite)

  • @sanils7260
    @sanils7260 Місяць тому

    10+25/2=17.50, 13+14/2=13.50 17.5*13.50=236.25

  • @adgf1x
    @adgf1x 19 днів тому

    99/15=33/5=6.6

  • @shobavp5777
    @shobavp5777 Місяць тому +1

    AB is not parallel to CD because AD =13, BC=14 if AD=BC, AB and CD parallel

    • @marinaasstra2604
      @marinaasstra2604 Місяць тому

      По условию же трапеция

    • @shivamrathaur7195
      @shivamrathaur7195 Місяць тому

      Bhai parallel hogi because AD and BC are transversal line not perpendicular distance between these parallel line.

  • @ShoaibAnwar-p7s
    @ShoaibAnwar-p7s Місяць тому

    17'- 6" × 13' - 6".

  • @田中勉-c7c
    @田中勉-c7c 2 місяці тому

    99/15は33/5と約分可能。

  • @ramesankd1604
    @ramesankd1604 Місяць тому

    17.5

  • @prossvay8744
    @prossvay8744 2 місяці тому

    Trapezoid area=1/2(10+25)(56/5)=196

  • @subbugowda4204
    @subbugowda4204 Місяць тому

    2 parellal sides divided by 2 into other 2 sides divided by 2 and if multiplied how ?

  • @karimmehdizadeh-wd8md
    @karimmehdizadeh-wd8md 22 години тому

    196

  • @juliocesargranafernandez2106
    @juliocesargranafernandez2106 2 місяці тому

    Se complica con un desarrollo tan extenso y es más fácil que la tabla del uno.

  • @wasimahmad-t6c
    @wasimahmad-t6c Місяць тому

    189.4

  • @Jaahquubel
    @Jaahquubel Місяць тому

    x = 99/15 = 33/5

  • @viswanathanlakshminarayana1576
    @viswanathanlakshminarayana1576 Місяць тому

    what abt nos 13, 17,, 19 , to divide by these nos

  • @quigonkenny
    @quigonkenny 2 місяці тому

    Draw AE, where E is the point on DC where AE amd BC are parallel. This creates parallelogram ABCE, with sides of 14 and 10, and triangle ∆AED with sides of 13, 14, and 25-10 = 15.
    Let ∠EDA = θ. By the law of cosines:
    cos(θ) = (AD²+ED²-AE²)/2(AD)ED
    cos(θ) = (13²+15²-14²)/2(13)(15)
    cos(θ) = (169+225-196)/390
    cos(θ) = 198/390 = 33/65
    sin²(θ) = 1 - cos²(θ) = 1 - (33/65)²
    sin²(θ) = 1- 1089/4225 = 3136/4225
    sin(θ) = √(3136/4225) = 56/65
    (1/2)(ED)h = (1/2)AD(ED)sin(θ)
    h = 13(56/65) = 56/5
    Trapezoid ABCD:
    [ABCD] = h(a+b)/2 = (56/5)(10+25)/2
    [ABCD] = (56/5)(35)/2 = 28(7) = 196 sq units

  • @sorourhashemi3249
    @sorourhashemi3249 2 місяці тому

    Thanks but so easy

  • @gnanadesikansenthilnathan6750
    @gnanadesikansenthilnathan6750 Місяць тому

    Nice problem

  • @venkatnagar27
    @venkatnagar27 28 днів тому

    Ans.210 sq.ft. Area

  • @daakudaddy5453
    @daakudaddy5453 2 місяці тому +1

    99/15 = 33/5
    Would have made calculatioj much simpler. I don't know why you chose not to simplify it further...

    • @MathBooster
      @MathBooster  2 місяці тому +1

      I just didn't noticed it at that time.

    • @imetroangola17
      @imetroangola17 2 місяці тому

      ​@@MathBoostero importante é que você resolveu! Também, é importante mostrar outras soluções! Matemática, sempre tem outras formas de chegar ao resultado.

  • @AshleyKimPascual
    @AshleyKimPascual 19 днів тому

    hard to think this one,,i cant pass this,1+1 =2. that's all ,,, in army when there is war you cannot think that,,

  • @wasimahmad-t6c
    @wasimahmad-t6c Місяць тому

    195.6519

  • @robertloveless4938
    @robertloveless4938 2 місяці тому +2

    I imagined method 2 right away. BUT, somewhere, I went astray and got the answer wrong. Oh well.

  • @abdelmoniemzamli2446
    @abdelmoniemzamli2446 2 місяці тому

    المساحة ١٩٦ وحدة مربعة

  • @soojin1
    @soojin1 2 місяці тому

    Area= 196

  • @adgf1x
    @adgf1x 19 днів тому

    alt.11.2

  • @dhanrajchaudhari5627
    @dhanrajchaudhari5627 2 місяці тому

    Ca is 25-x

  • @ismetgj
    @ismetgj 28 днів тому

    Nein falsch = 236

  • @何柏希
    @何柏希 2 місяці тому

    Why you guys not use S=

    • @Augustus9720
      @Augustus9720 2 місяці тому +1

      S mean surface, A means area but they are actually the same just because the difference of habit.习惯不同而已

  • @mathewlopes5657
    @mathewlopes5657 12 днів тому

    Your method is very lengthy. After getting x = 6.6 apply pythagorus theorem to get h= 11.2 and apply formula of trapezium you will get answer 198.

  • @surajrajanayake-eq3fy
    @surajrajanayake-eq3fy 2 місяці тому +1

    2nd Method
    13.58min
    What is S

    • @vivificateurveridique1420
      @vivificateurveridique1420 2 місяці тому

      he applied: To calculate the area of a triangle using its semi-perimeter, you can use Heron's formula. Here’s how it works:
      Calculate the semi-perimeter (s):
      𝑠
      =
      𝑎
      +
      𝑏
      +
      𝑐
      2
      s=
      2
      a+b+c

      where
      𝑎
      a,
      𝑏
      b, and
      𝑐
      c are the lengths of the sides of the triangle.
      Calculate the area (A) using Heron's formula:
      𝐴
      =
      𝑠
      (
      𝑠

      𝑎
      )
      (
      𝑠

      𝑏
      )
      (
      𝑠

      𝑐
      )
      A=
      s(s−a)(s−b)(s−c)

  • @isaacaddae4207
    @isaacaddae4207 Місяць тому

    Please I won't JHs2 and 3

  • @rgcriu2530
    @rgcriu2530 2 місяці тому

    👍👍👍👍

  • @wasimahmad-t6c
    @wasimahmad-t6c 23 дні тому

    It is not trengle

  • @SuperMak360
    @SuperMak360 Місяць тому

    25 or 15 ??

  • @SatyanarayanaMudunuri
    @SatyanarayanaMudunuri 2 місяці тому

    what us yesquaire? Awful pronunciation and explanation

  • @wasimahmad-t6c
    @wasimahmad-t6c 23 дні тому

    196.437