Simple Geometry Puzzles You Can't Solve

Re:Simple Geometry Puzzles You Can't Solve by ingenium on Monday December 03, 2007 @02:33AM (#85538)

Look at my work before you mod me down. The lines I drew were not drawn with a ruler. If x is 10, then DE is 60 degrees from the line running through D (not 50), parallel to AB, just like the angle DBA.

If a protractor says one thing, and the math using known values says another, I'm going to trust the math.

I see where according to the figure, triangle ADE must be isosceles, but I don't trust that the figure is actually drawn to scale. All the measurements of angles I got by calculations. Can you find a flaw in one of those?

[ Parent | on HN ]

Re:Simple Geometry Puzzles You Can't Solve by naish on Monday December 03, 2007 @02:41AM (#85539)

Check again. The figure is to scale. I worked it out first and then checked with a protractor. Your assumption that the diagonals within the trapezoids are parallel is incorrect. As a result, angles that you have assigned to the triangles in the upper trapezoid are also incorrect. The fact that triangle ADE is not isosceles makes it impossible for x to be 10.

[ Parent | on HN ]

Re:Simple Geometry Puzzles You Can't Solve by rms on Monday December 03, 2007 @03:18AM (#85545)

> Your assumption that the diagonals within the trapezoids are parallel is incorrect.

Do you mean his assumption that the diagonals within the trapezoids are congruent is incorrect? I'd be curious to see your diagram or proof to see where you differ. Obviously, it makes a lot more sense that the diagram is drawn to scale.

[ Parent | on HN ]

Re:Simple Geometry Puzzles You Can't Solve by naish on Monday December 03, 2007 @11:16AM (#85622)

Here is my solution: http://fernlabs.com/Problem1Solution.png

[ Parent | on HN ]