I am trying to understand the coding given in the following link How to draw a coffee cup, where the ellipse's radius are defined in terms of ratio's. My doubt is, "How to interpret such ratios physically"? I also found such ratios in bodeplot package example.
An answer for the mathematical part of the question.
5/4/2 uses the division operator that is left associative. That means, the expression is evaluated from left to right:
5/4/2 = (5/4)/2 = 5/8 = 0.625
I think the author has chosen
0.625 to show a little better, how
the value is calculated. For example, a previous line contains
x radius=5/4 and
5/4/2 was used in
x radius=5/4/2. Then, it is easier (without calculations) to see, that 5/4/2 is the half of 5/4 as that 0.625 is the half of 1.25.