

Triangle Dissection Paradox - MikeCapone
http://mathworld.wolfram.com/TriangleDissectionParadox.html

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teilo
Not a paradox, but an optical illusion.

Really, not even that. If you look at where the grid lines intersect, you can
see that though the angles of the red and yellow triangles are similar, they
are not exactly the same.

In other words: the composite triangle is not really even a triangle, but a
4-sided polygon with one very obtuse angle.

~~~
InclinedPlane
Not even an optical illusion, more of an optical slight-of-hand. 2/5ths and
3/8ths are quite close fractions, but they are not the same. Neither of the
figures are triangles, they are just very close to triangles. In each case
there is a triangular piece either missing or added on to the perceived
triangle.

The reason this deception works so well is because the deviation from the
perceived triangle is only half of the extra area bit and that area is spread
across the longest dimension of the figure (the hypotenuse of the perceived
triangle).

This is a good lesson in avoiding letting your eye and your gut lead you to
conclusions. Neither are precision instruments.

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francoisdevlin
Lots of people don't have the discipline for math, news at 11.

