Challenging similarity problem | Similarity | Geometry | Khan Academy

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  • เผยแพร่เมื่อ 24 ธ.ค. 2024

ความคิดเห็น • 35

  • @junk11111111
    @junk11111111 13 ปีที่แล้ว +7

    Google Khan Academy and scroll down in Khan's website for other subjects that he speaks on like this:
    Physics, Biology, Chemistry, Math (algebra, Calc, Trig, Stats, etc, etc), Art History, Computer Science, Economics, Finance, History, SAT Preparation, etc, etc, etc.
    If your in school take a look and see if Khan has talked about the subject. He's financed by the Gates foundation and Google, etc.
    His vision: Eventually have all university level education online and below for free

  • @InspectorA-r2e
    @InspectorA-r2e 7 ปีที่แล้ว +11

    HARD.. I couldn't think about y-x/y = 1-x/y .

    • @horrorayaan-1278
      @horrorayaan-1278 3 ปีที่แล้ว +5

      (y - x)/y = y/y - x/y so there for y/y will be 1 so we can wright it as 1 - x/y

  • @subhaompatro07
    @subhaompatro07 10 หลายเดือนก่อน

    If it would be a mcq then we would just have to remember a formula in these questions i.e. 1/AB + 1/DE = 1/CF (atq) we just have to practice more and learn some formulas to solve problems faster

  • @quagmire444
    @quagmire444 12 ปีที่แล้ว +1

    i distinctly remember this problem being given to me in 8th grade. i think i can figure it out agian :O

  • @shankernarayan5028
    @shankernarayan5028 5 ปีที่แล้ว +2

    A simpler method is to consider the cases of parallel lines.this leads you to finding similar triangles and then by basic proportionality theorem we can easily solve.i solved it in 3 min with use of this method.ab and de are parallel by sum of cointerior angles rule. So u will find that ABC and dec are similar. Using this we can find ac:CE and then find ae and then by basic proportionality theorem we can find CF .

    • @Hotliverbaby
      @Hotliverbaby 4 ปีที่แล้ว

      How did u find ac:ce

  • @MichaelHollomon
    @MichaelHollomon 10 หลายเดือนก่อน

    This was tough, but fun! Did it 3 times to make sure I really understand it. I would never have passed this test in high school lol

  • @mattswimmer1
    @mattswimmer1 13 ปีที่แล้ว +2

    This is cool :)

    • @namari9407
      @namari9407 4 ปีที่แล้ว +2

      it's been 9 years .... how are you, i wonder how your journey been. have a beautiful life ahead :)

  • @jemappellelanoosh1743
    @jemappellelanoosh1743 12 ปีที่แล้ว

    Wow !!!

  • @ggmm117
    @ggmm117 13 ปีที่แล้ว

    awesome

  • @zakesucgang2567
    @zakesucgang2567 2 ปีที่แล้ว

    can we solve it if we use 9/CF=y/y-x?????

  • @vismithad9310
    @vismithad9310 7 ปีที่แล้ว +1

    Sir there is a question "if the areas of two similar triangles are equal prove that they are congruent ." please help me. my teacher are just avoiding me and not answering me plz help me.

    • @aadyachinubhai
      @aadyachinubhai 7 ปีที่แล้ว +1

      Since Areas of 2 Similar Triangles are Equal,
      We know that :
      area(ABC)÷area(PQR) = Square of their Corresponding Sides.
      Thus, Squares of all sides are equal.
      Thus, All sides are equal.
      Thus, By SSS ,
      Triangle(ABC)≅Triangle(PQR)

    • @travelwithkrish2530
      @travelwithkrish2530 6 ปีที่แล้ว

      What a silly questions
      Common logic

  • @super_walrus
    @super_walrus 11 ปีที่แล้ว

    HMMM. Isn't also possible to say the linesAB, CF, DE are parrallel and then find CF by doing AB times DE divided by AB plus DE on this particular problem?

    • @d.anthonythacker5107
      @d.anthonythacker5107 10 ปีที่แล้ว

      Good to hear. I will hold you to it if it sux friend! Joking! Stop in some time!

    • @d.anthonythacker5107
      @d.anthonythacker5107 10 ปีที่แล้ว

      A great book called "starship troopers" by Heinlein is such a great book I've actually read it 3x. The stupid, stupid movies match the book only in name. The right sfx and director i.e. Ridley Scott.

  • @amans2
    @amans2 7 ปีที่แล้ว +1

    Directly use the formula.. (9*12)/(9+12)

  • @damienglover2979
    @damienglover2979 6 ปีที่แล้ว

    Why is FE y-x? That line is longer than x. How did you determine that?

    • @legacies9041
      @legacies9041 3 ปีที่แล้ว

      He did not

    • @Deboned_butter
      @Deboned_butter 2 ปีที่แล้ว +1

      For explanation, say the y-x is z.
      *VIA PROOF:*
      y is the length of x and z combined (AKA x+z=y)
      Subtract x from both sides to get z=y-x.
      *VIA LOGIC:*
      z is the length of y but without the x
      z=y… minus x
      *VIA EXAMPLE:*
      x=3, z=5, y=z+x therefore y=8
      8-3=5, every variable lines up to y-x=z
      X=6, z=7, y=z+x therefore y=13
      13-6=7, every variable lines up to y-x=z

  • @sunny.xi1
    @sunny.xi1 7 ปีที่แล้ว +2

    complicated much???

  • @travelwithkrish2530
    @travelwithkrish2530 6 ปีที่แล้ว +1

    You just lengthened it up its just a three step sum.

    • @sanchitvarshney8405
      @sanchitvarshney8405 5 ปีที่แล้ว

      How is it a 3 step sum?

    • @MichaelHollomon
      @MichaelHollomon 10 หลายเดือนก่อน

      ⁠@@sanchitvarshney8405we know the triangles are similar given the congruent right angles and shared angles. And since AB = 9 and DE = 12 are given, we can just skip straight to CF/9 + CF/12 = 1, and algebraically solve for CF.
      But it was fun and instructive working it through step by step.

    • @alcamisticrblx1079
      @alcamisticrblx1079 8 หลายเดือนก่อน +1

      @@MichaelHollomon but if we skipped the 1st couple steps, how would we know that CF/9 + CF/12 is equal to 1? Where did 1 come from?

    • @MichaelHollomon
      @MichaelHollomon 8 หลายเดือนก่อน

      @@alcamisticrblx1079 1 just comes from the fact that 1 times CF equals CF. But 1 is actually an irrelevant value. You could just as easily replace it with X. In which case you would end up with CF = 36X/7, instead of the simpler CF = 36/7

  • @uklearninghub9058
    @uklearninghub9058 6 ปีที่แล้ว

    Sir i have question please help me to solve this

    • @bestia270
      @bestia270 ปีที่แล้ว

      Did you solve it yet

  • @amypan2608
    @amypan2608 7 หลายเดือนก่อน

    Anyone 2024?

  • @madmaxonliner
    @madmaxonliner 12 ปีที่แล้ว

    Your assumption that "AB and DE are parallel" is not true because there's no indication that they actually are! that was never mentioned in the problem.

    • @spiderjump
      @spiderjump 7 ปีที่แล้ว +2

      Sam Rockwell angles ABE and DEB are 90 deg each which add up to 180 . therefore the 2 lines are parrallel

    • @shankernarayan5028
      @shankernarayan5028 5 ปีที่แล้ว

      Two lines are parallel if their corresponding cointerior angles sum up to 180 .this is the case here