Given $x,y,a,b$ such that $x^2 + xy = a^2+ab$, with $x > y$ and $a>b$.
$2(x^2+xy) = 2(a^2+ab) \implies (x^2+y^2) + 2xy + (x^2-y^2) = (a^2+b^2) + 2ab + (a^2-b^2)$. The three terms on each side form a triple.
For example:
Let $x=8,y=7,a=10,b=2$. Then, $113+112 + 15 = 104+40+96$. Furthermore, $15^2 + 112^2 = 113^2$ and $40^2+96^2=104^2$.
More exciting: Let $x=48,y=44,a=64,b=5$. Then, $4224+ 368 + 4240 = 640+4071+4121$. Further $4224^2 + 368^2 = 4240^2$ and $640^2+4071^2=4121^2$.
Even bigger: Let $x=87,y=43,a=78,b=67$. Then, $7482+ 5720 + 9418 = 10452+1595+10573$. Further $7482^2 + 5720^2 = 9418^2$ and $10452^2+1595^2=10573^2$.
Finally, the biggest: $x=99,y=61,a=96,b=69$. Then, $12078+ 6080 + 13522 = 13248+4455+13977$. Further $12078^2 + 6080^2 = 13522^2$ and $13248^2+4455^2=13977^2$.
You can explore further.
EDIT : Just adding another : $x=10000 ,y= 287 ,a=10125 ,b= 35$ , with $5740000 + 99917631+100082369=708750+102514400+102516850$.