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View Full Version : Can someone please explain this to me?

Jorge Sanchez
08-12-2005, 10:06 AM
I have been trying to figure this out forever, but why does this happen? Is it an illusion or is there a mathematical explanation for it?

http://www.simeonmagic.com/triangle/triangle1.htm

Gyno Rhino
08-12-2005, 10:12 AM
Neither composite shape is truly a triangle.

Look closely at the diagonal. It is NOT a straight line.

Jorge Sanchez
08-12-2005, 10:15 AM
Good call. Thanks.

BigCorey75
08-12-2005, 10:23 AM
true, took me a while to see it but true

meltedtime
08-12-2005, 10:54 AM
Dif. angle on the triangles. Look at the large triangle. Follow it down to the third square and compare to the other one. A little optical illusion trick.

endoplasm
08-12-2005, 11:57 AM
http://www.grand-illusions.com/triangle1.htm

Built
08-12-2005, 12:09 PM
It's easy to spot if you look at the slopes of the diagonals of the two smaller triangles, and of the composite "triangle".

The slope of the red triangle has a slope of 3/8 = .375
The slope of the green triangle has a slope of 2/5 = .400

The composite "triangle" appears to have a diagonal slope of 5/13 = .385

Within rounding, these diagonals all have very similar slopes. But they must be identical to satisfy the needs of triangle similarity.

If the red and green triangles were similar, their diagonals would have the same slopes. Because they do not, the composite shape is not a triangle. It is, in fact, a quadrangle.

TwiloMike
08-12-2005, 12:22 PM
Built is totally right. A little bit of difference goes a long way. Nice trick, though (displaying it on a graph background).

David
08-12-2005, 12:43 PM
It's easy to spot if you look at the slopes of the diagonals of the two smaller triangles, and of the composite "triangle".

The slope of the red triangle has a slope of 3/8 = .375
The slope of the green triangle has a slope of 2/5 = .400

The composite "triangle" appears to have a diagonal slope of 5/13 = .385

Within rounding, these diagonals all have very similar slopes. But they must be identical to satisfy the needs of triangle similarity.

If the red and green triangles were similar, their diagonals would have the same slopes. Because they do not, the composite shape is not a triangle. It is, in fact, a quadrangle.

What are you, an intellectual?

Lol