Geometric Impossibility?? I found this puzzle online ...?
... which has me, well, puzzled! The upper image shows 4 geometric shapes within a triangle, completely filling the space. The lower image shows the same four shapes within the same triangle, but not filling the entire space. How is this possible??? The combined surface area of the four shapes has to be constant, regardless of how they are arranged, right? What am I overlooking here? Is this some kind of trick??
Haha, I know the answer. If you look at the point in the middle of the hypotenuse of the triangle with no gap, you will see that the slopes of the lines on either side of it are not the same. In other words the upper line (hypoenuse) is bowed down to eliminate the area that is present as a gap in the lower triangle. It is extremely deceiving though.
I do a lot of wood working were mesurements have to be exact. Get yourself a good ruller and measure the parts in the pictures as I did, you will see their not the same sizes, They very from 1/16" to as much as 1/8". If each part were the exact same size in each picture, they would fit exactly the same. I measured each part over and over again, there not the same sizes.
Since the green triangle has θ = arctan 2 / 5 = 21.8°, and the red triangle has θ = arctan 3 / 8 = 20.6°, these are not congruent, ie. the hypotenuse is not truly straight in either diagram.