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Mensa Triangle

  1. Nov 16, 2006 #1
    Ok, I've just signed up to this forum and i see there are alot of very smart people and i just wondered if anyone knows the answer to the mensa triangle problem. Ive sat and stared at it for hours and still i have no answer. Any theories.
  2. jcsd
  3. Nov 16, 2006 #2
    Use the search function. There have been several threads about this already.

    Bottom line: Look at the slopes, one of the shapes isnt even a real triangle.

    For example, the second triangle's green part has a steeper slope than the red part.

    EDIT: The green triangle slopes don't equal the red triangle slope.

    EDIT2: To see this, line up a ruler to the first triangle, connect the bottom left to the top right. Notice how the actual "triangle" is slightly below this. Do the same to the second one, and you will see the "triangle" is slightly bent upwards. So the change in that area is that extra square.
    Last edited: Nov 16, 2006
  4. Nov 16, 2006 #3
    Damn you make it all sound easy but i see what you mean. Ive just been counting the number of squares per triangle. Thats where ive been going wrong. Cheers
  5. Nov 17, 2006 #4


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    Oh, that thing! Check the slopes of the hypotenuse of the red right triangle: it has base 8 and height 3; slope 3/8. Now check the slope on the green right triangle: it has base 5 and height 2; slope 2/5. Since those are not the same, that "hypotenuse" of the entire "triangle" is NOT a straight line and it isn't really a triangle at all.
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