Think of a triangle such that the length of all sides are $1$.
Note that the sum of the two black sides is always $2$.
So, the sum of the black sides in the last triangle is $2$.
Note that the bottom ...
I am of course well aware that distances in Euclidean geometry are calculated from the Pythagorean theorem. This is more of a conceptual question.
My question may also be formulated as follows:
If we ...