Triangle Theorem Study

My first failed attempt at proving the equilateral triangle theorem in the post below. Notice how I mistakenly thought an equilateral triangle’s centroid is located one-third up the side length of the triangle rather than the height distance, so I’m missing the needed factors of Sqrt[3]/2. Also, I had labelled the three vertices of the starting triangle as z1, z2 & z3 rather than z1, z1 + z2 & z1 + z2 + z3. Needless to say, the math refuses to work out with these problems. This gave me fits for a little while.
Eagle-eyed viewers will also notice that I was thinking about the 2^32 estimation problem on this same piece of paper.