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

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  • Опубликовано: 19 янв 2025

Комментарии • 80

  • @AmirgabYT2185
    @AmirgabYT2185 4 месяца назад +10

    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.

  • @imetroangola17
    @imetroangola17 4 месяца назад +7

    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 4 месяца назад

      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 4 месяца назад

      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 4 месяца назад +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 4 месяца назад

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

    • @RAG981
      @RAG981 4 месяца назад

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

  • @dhorasokoli47
    @dhorasokoli47 4 месяца назад +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

    • @TyyylerDurden
      @TyyylerDurden 3 месяца назад

      Yeah, solved it the same way.

  • @kaliprasadguru1921
    @kaliprasadguru1921 2 месяца назад +1

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

  • @RealQinnMalloryu4
    @RealQinnMalloryu4 4 месяца назад +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).

  • @josephkt6830
    @josephkt6830 2 месяца назад +1

    Very good illustration.thanks

  • @baselinesweb
    @baselinesweb 3 месяца назад

    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.

  • @murdock5537
    @murdock5537 4 месяца назад +12

    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

  • @kateknowles8055
    @kateknowles8055 2 месяца назад

    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 .

  • @srizzio
    @srizzio 3 месяца назад

    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.

  • @Sekar-888
    @Sekar-888 8 дней назад

    Formula S=1/2 x h x (a+b)sq. unites.
    Draw vertical line at an angle of 90°
    That's the height.. In the Trapezium abcd is the 4 points. Use π2korian theorem.. we get the answer.

  • @wes9627
    @wes9627 3 месяца назад

    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.

  • @alster724
    @alster724 3 месяца назад

    Nice use of the Herons on Method 2

  • @satrajitghosh8162
    @satrajitghosh8162 4 месяца назад +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

  • @santiagoarosam430
    @santiagoarosam430 4 месяца назад

    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.

  • @shobavp5777
    @shobavp5777 3 месяца назад +1

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

    • @marinaasstra2604
      @marinaasstra2604 3 месяца назад

      По условию же трапеция

    • @shivamrathaur7195
      @shivamrathaur7195 3 месяца назад

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

  • @subbugowda4204
    @subbugowda4204 2 месяца назад

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

  • @adgf1x
    @adgf1x 3 месяца назад +1

    ar.=196sq unit.ans

  • @subbaraob8474
    @subbaraob8474 2 месяца назад

    Super solution

  • @viswanathanlakshminarayana1576
    @viswanathanlakshminarayana1576 3 месяца назад

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

  • @daakudaddy5453
    @daakudaddy5453 4 месяца назад +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  4 месяца назад +1

      I just didn't noticed it at that time.

    • @imetroangola17
      @imetroangola17 4 месяца назад

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

  • @juliocesargranafernandez2106
    @juliocesargranafernandez2106 4 месяца назад

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

  • @quigonkenny
    @quigonkenny 4 месяца назад

    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

  • @adgf1x
    @adgf1x 9 дней назад

    ar.trapz.=196 sq.unit.ans

  • @田中勉-c7c
    @田中勉-c7c 4 месяца назад

    99/15は33/5と約分可能。

  • @adgf1x
    @adgf1x Месяц назад

    at of trapziu35×5.6=196. ans

  • @prossvay8744
    @prossvay8744 4 месяца назад

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

  • @sanils7260
    @sanils7260 3 месяца назад

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

  • @robertloveless4938
    @robertloveless4938 4 месяца назад +2

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

  • @adgf1x
    @adgf1x Месяц назад

    alt. of trap=11.2 unit.

  • @sorourhashemi3249
    @sorourhashemi3249 4 месяца назад

    Thanks but so easy

  • @ramesankd1604
    @ramesankd1604 2 месяца назад

    17.5

  • @AhmadNiazy-s5b
    @AhmadNiazy-s5b 11 дней назад

    36.50

  • @surajrajanayake-eq3fy
    @surajrajanayake-eq3fy 4 месяца назад +1

    2nd Method
    13.58min
    What is S

    • @vivificateurveridique1420
      @vivificateurveridique1420 4 месяца назад

      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)

  • @gnanadesikansenthilnathan6750
    @gnanadesikansenthilnathan6750 3 месяца назад

    Nice problem

  • @wasimahmad-t6c
    @wasimahmad-t6c 2 месяца назад

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

  • @freel0077
    @freel0077 Месяц назад

    Simple is :
    Draw 2, 90^ triangles and one rectangle from this shape.
    Area of 90^ triangle= 1/2 ab
    Area of rectangle = ab
    ; a is length, b is height.
    Add all.

  • @何柏希
    @何柏希 4 месяца назад

    Why you guys not use S=

    • @Augustus9720
      @Augustus9720 4 месяца назад +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

  • @ShoaibAnwar-p7s
    @ShoaibAnwar-p7s 3 месяца назад

    17'- 6" × 13' - 6".

  • @wasimahmad-t6c
    @wasimahmad-t6c 3 месяца назад

    189.4

  • @Misha-g3b
    @Misha-g3b 18 дней назад

    196 un.²

  • @mathewlopes5657
    @mathewlopes5657 2 месяца назад

    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.

  • @hirondas4563
    @hirondas4563 12 дней назад

    AB II DC and NOT AB II CD.

  • @Jaahquubel
    @Jaahquubel 3 месяца назад

    x = 99/15 = 33/5

  • @abdelmoniemzamli2446
    @abdelmoniemzamli2446 3 месяца назад

    المساحة ١٩٦ وحدة مربعة

  • @adgf1x
    @adgf1x 2 месяца назад

    alt.11.2

  • @huzrinebi3701
    @huzrinebi3701 26 дней назад

    aka mundsi shqip jufalemderit

  • @venkatnagar27
    @venkatnagar27 2 месяца назад

    Ans.210 sq.ft. Area

  • @AshleyKimPascual
    @AshleyKimPascual 2 месяца назад

    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 3 месяца назад

    195.6519

  • @DB-lg5sq
    @DB-lg5sq 3 дня назад

    بسط
    99/15 = 33/5

  • @adgf1x
    @adgf1x Месяц назад

    altitude=11.2

  • @dhanrajchaudhari5627
    @dhanrajchaudhari5627 4 месяца назад

    Ca is 25-x

  • @karimmehdizadeh-wd8md
    @karimmehdizadeh-wd8md Месяц назад

    196

  • @isaacaddae4207
    @isaacaddae4207 3 месяца назад

    Please I won't JHs2 and 3

  • @soojin1
    @soojin1 4 месяца назад

    Area= 196

  • @rgcriu2530
    @rgcriu2530 4 месяца назад

    👍👍👍👍

  • @wasimahmad-t6c
    @wasimahmad-t6c 2 месяца назад

    It is not trengle

  • @ismetgj
    @ismetgj 2 месяца назад

    Nein falsch = 236

  • @SuperMak360
    @SuperMak360 3 месяца назад

    25 or 15 ??

  • @MuthuramBalaganesh
    @MuthuramBalaganesh 9 дней назад

    .54ceñt

  • @SatyanarayanaMudunuri
    @SatyanarayanaMudunuri 4 месяца назад

    what us yesquaire? Awful pronunciation and explanation

  • @MuthuramBalaganesh
    @MuthuramBalaganesh 9 дней назад

    ௨3௬.…௨5

  • @wasimahmad-t6c
    @wasimahmad-t6c 2 месяца назад

    196.437

  • @nenetstree914
    @nenetstree914 Месяц назад

    196