Tuesday, August 28, 2018

geometry - 20 right isosceles triangles into a square


Similar: Unlucky tiling: Arrange thirteen right isosceles triangles into a square


Five graded difficulty isosceles right triangle into square tilings


Two difficult "Seventeen right isosceles triangles into a square" tilings


The challenge is to fit the smallest $20$ integer-sided scaled right isosceles triangles into a square with diagonal $46$


For convenience, I list the areas of the triangles:


$1, 2, 4, 8, 9, 16, 18, 25, 32, 36, 49, 50, 64, 72, 81, 98, 100, 121, 128, 144$


There are four ways of doing it (not two as originally posted). A brave person it would be who tackled this by hand.


By way of illustration/clarification, here are the right isosceles triangles of area


$1, 2, 4, 9, 16, 18, 50$



arranged into a $10\times 10$ square:


10x10_7



Answer



Here are at least two solutions (up to reflection and rotation)



enter image description here
The trapezoid outlined in red can be flipped.
enter image description here
This is presumably the other "substantially different" solution (not counting the above trapezoid flip as different).




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