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That damn triangle

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  • M Marc Clifton

    http://www.knowledgeautomation.com/graphics/triangle.JPG[^] :-D Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
    Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
    Every line of code is a liability - Taka Muraoka
    Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"

    J Offline
    J Offline
    John Honan
    wrote on last edited by
    #36

    Ah! Thank you! :rose: I am a 'visual' person, so that simple diagram really helped. :) The insanity is starting to ease off now. :rolleyes: John www.silveronion.com[^]

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    • S Stan Shannon

      Mike Mullikin wrote: The area difference between the convex and concave is exactly the area of the missing block. I suppose my problem than is that I simply see no "illusion". All I see are two rectangles, one 5 x 3 and the other 8 x 2, entirely independent of the triangles, regardless of how you draw them. It is only an illusion if you try to make an area of a triangle problem out of it, which it obviously isn't. You could change those triangles as much as you please, and I just don't see how the rectangles change any at all. Hell, you could convert both triangles into squares and nothing changes. The hole is still there.

      R Offline
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      RChin
      wrote on last edited by
      #37

      Stan Shannon wrote: I suppose my problem than is that I simply see no "illusion". Having spent ages looking at it myself, My co-worker came over, took one look at it and actually saw the 'bends' in the 'pseudo-triangles'. It may have something to do with him having weird astigmatism. But I was not pleased that it took him so quickly to see the fault.:)


      "..Even my comments have bugs!"
      Inspired by Toni78

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      • J John Honan

        Ah! Thank you! :rose: I am a 'visual' person, so that simple diagram really helped. :) The insanity is starting to ease off now. :rolleyes: John www.silveronion.com[^]

        M Offline
        M Offline
        Marc Clifton
        wrote on last edited by
        #38

        It's funny, if you print it and cut out the pieces, you can actually see the differences in the two triangles. And you can reproduce the second drawing too. This'll make a great illusion for my kid's 7th grade class next year! Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
        Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
        Every line of code is a liability - Taka Muraoka
        Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"

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        • J John Honan

          I'm sorry, but I'm going to have to bring this 'optical illusion' thread up again as its driving me mad. http://www.codeproject.com/lounge.asp?msg=528308#xx528308xx[^] http://www.briandela.com/files/picture.gif[^] I read the replies, but I must be stupid or something, cause none of them made sense. This triangle problem has occupied my thoughts since this time yesterday. I've recreated versions of it in Excel and Paintshop Pro, and still can't get my head around it!!! Help!!!! :eek::eek: Basically, the surface area of both large triangles is 32.5 squares. And both triangles ARE the same, AND the hypotenuse is a straight line. Why doesn't it add up? :(( John www.silveronion.com[^]

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          Venet
          wrote on last edited by
          #39

          But it was nice mind boggling (or whatever the word is) :):):) Regards, Venet. Donec eris felix, multos numerabis amicos.

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          • V Venet

            But it was nice mind boggling (or whatever the word is) :):):) Regards, Venet. Donec eris felix, multos numerabis amicos.

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            Stan Shannon
            wrote on last edited by
            #40

            The area of a triangle of angle 2:5 extended for a width of 13 units is 33.8 square units. The area of a triangle of angle 3:8 extended for a width of 13 units is 31.7 square units. for a result of 2.1 square units difference between the two, yet the "hole" is obviously one squre unit. Precisely how does that translate into a solution? You guys are on drugs. The hole is there because its there, and would be there no matter how you draw the damned trianagles. Look at the diagram for Pete's sake.

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            • R RChin

              Stan Shannon wrote: I suppose my problem than is that I simply see no "illusion". Having spent ages looking at it myself, My co-worker came over, took one look at it and actually saw the 'bends' in the 'pseudo-triangles'. It may have something to do with him having weird astigmatism. But I was not pleased that it took him so quickly to see the fault.:)


              "..Even my comments have bugs!"
              Inspired by Toni78

              S Offline
              S Offline
              Stan Shannon
              wrote on last edited by
              #41

              The problem, though, is that I am right and the rest of you guys are wrong. There is no illusion, the math just does not work out. Am I the only one here who can calculate the area of a triangle?

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              • M Marc Clifton

                It's funny, if you print it and cut out the pieces, you can actually see the differences in the two triangles. And you can reproduce the second drawing too. This'll make a great illusion for my kid's 7th grade class next year! Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
                Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
                Every line of code is a liability - Taka Muraoka
                Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"

                S Offline
                S Offline
                Stan Shannon
                wrote on last edited by
                #42

                You'd better hope that none of them know simple geometry.

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                • S Stan Shannon

                  You'd better hope that none of them know simple geometry.

                  M Offline
                  M Offline
                  Marc Clifton
                  wrote on last edited by
                  #43

                  Stan Shannon wrote: You'd better hope that none of them know simple geometry. So far, so good. :-D Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
                  Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
                  Every line of code is a liability - Taka Muraoka
                  Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"

                  1 Reply Last reply
                  0
                  • S Stan Shannon

                    The area of a triangle of angle 2:5 extended for a width of 13 units is 33.8 square units. The area of a triangle of angle 3:8 extended for a width of 13 units is 31.7 square units. for a result of 2.1 square units difference between the two, yet the "hole" is obviously one squre unit. Precisely how does that translate into a solution? You guys are on drugs. The hole is there because its there, and would be there no matter how you draw the damned trianagles. Look at the diagram for Pete's sake.

                    M Offline
                    M Offline
                    Marc Clifton
                    wrote on last edited by
                    #44

                    Stan Shannon wrote: The hole is there because its there, and would be there no matter how you draw the damned trianagles. A=bh/2 The red triangle is 8*3/2, = 12 sq. u. The green triangle is 5*2/2, = 5 sq. u The blocks are 15 sq. u 12+5+15=32 sq. u The whole triangle is 13*5/2, = 32.5 The hole is actually 1/2 sq. unit, but by maintaining a constant base length, it can be made to appear to be 1 sq. unit. In the top diagram, the triangle bulges out 1/2 sq. unit, and in the bottom triangle, it caves in 1/2 sq. unit. Since we're comparing to a perfect triangle (which this is not), the caving in on the bottom drawing by 1/2 sq. unit adds the other piece, thus making a full sq. unit hole. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
                    Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
                    Every line of code is a liability - Taka Muraoka
                    Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"

                    S 1 Reply Last reply
                    0
                    • M Marc Clifton

                      Stan Shannon wrote: The hole is there because its there, and would be there no matter how you draw the damned trianagles. A=bh/2 The red triangle is 8*3/2, = 12 sq. u. The green triangle is 5*2/2, = 5 sq. u The blocks are 15 sq. u 12+5+15=32 sq. u The whole triangle is 13*5/2, = 32.5 The hole is actually 1/2 sq. unit, but by maintaining a constant base length, it can be made to appear to be 1 sq. unit. In the top diagram, the triangle bulges out 1/2 sq. unit, and in the bottom triangle, it caves in 1/2 sq. unit. Since we're comparing to a perfect triangle (which this is not), the caving in on the bottom drawing by 1/2 sq. unit adds the other piece, thus making a full sq. unit hole. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
                      Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
                      Every line of code is a liability - Taka Muraoka
                      Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"

                      S Offline
                      S Offline
                      Stan Shannon
                      wrote on last edited by
                      #45

                      If I take an arbitrary rectangle (X,Y) and select two arbitrary regions from it (X1,Y1) and (X2,Y2) such that X = X1 + X2 and Y = Y1 + Y2 than I get the following result: The difference between the areas of the triangles formed by the three regions is: (XY/2) - ((X1Y2)/2 + (X2Y1)/2 + X2Y2 ) this expands to: ((X1 + X2)(Y1 + Y2))/2 - ((X1Y2)/2 + (X2Y1)/2 + X2Y2 ) and: (X1Y1 + X1Y2 + X2Y1 + X2Y2)/2 - ((X1Y2)/2 + (X2Y1)/2 + X2Y2 ) or: (X1Y1)/2 + (X1Y2)/2 + (X2Y1)/2 + (X2Y2)/2 - ((X1Y2)/2 - (X2Y1)/2 - X2Y2 which reduces to: (X1Y1)/2 - (X2Y2)/2 or: (X1Y1 - X2Y2) / 2 but: X1Y1 - X2Y2 is merely the difference between the two originally selected arbitrary areas within the rectangle. This is a trivial result, and prooves that any time you take any two arbitrary points within a rectangle you get results similar to those in the "illusion". So, as I originally posted - you are merely comparing two rectangular areas, you do not need to calculate angles or anything else - the results are obvious and trivial regardless of where you select the points. In the case of the illusion, the "hole" is there merely because you subtracted a 15 square unit region from a 16 square unit region. "More capitalism, please..."

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