How to create rhombus described on rectangle

Question

Let's say I have a rectangle of width w and height h centered at coordinate origin. How I can create rhombus described on this rectangle? Additional requirement is that rhombus width should be twice as height. Any ideas?

Answer 1

Clue: you need that rectangle corner point (w/2, h/2) belongs to segment (0, a)-(2*a, 0).

So write line equation for this segment, substitute corner coordinates into that equation, solve it for unknown a parameter (half of vertical diagonal of the rhombus)