Hi,

If $\displaystyle D>C\geq B>A>0$

and we have 3 squares in arithmetic progression $\displaystyle x_0, x_1, x_2$ where $\displaystyle x_2-x_1=x_1-x_0=d$

can $\displaystyle d=2(A^2-B^2)CD$ ?

Thanks for any help\pointers