<Tri-2025-2257>, hint

Let r=(1/2)(a-2d), a=a b=a-d, c=a+d,  2s=a+b+c

[ABC]=rs={s(s-a)(s-b)(s-c)}^(1/2)

By calculation a=4d acquired. r=d, a=4d. b=3d, c=5d

Hence 3,4,5 a right triangle.