Originally posted by: LurchFrinky
It is difficult to tell from the pictures, but the red and green triangles are not proportional, that is, the slopes of their hypotenuse(s?) are not the same. The green triangle is 5 units wide by 2 units tall. If it were scaled up to 3 units tall, it would be 7.5 unit wide. Neither of the combined triangles actually has a straight hypotenuse. The top one is kinked in, while the bottom one is kinked out.
I don't think there is any correlation with the Fibonacci series.