Equation with three variables I am confused as how to solve an equation with three squared variables to get its integer solutions? As: 
$$x^2+y^2+z^2=200$$
Thanks!

If you are doing it to find solution to your previous question about the area of that triangle then you should use heron's formula and simplify it in terms of $x, y, z$ like,
$\sqrt{s(s-a)(s-b)(s-c)}=\dfrac{1}{4}\sqrt{(x+y+z)(x+y-z)(x-y+z)(-x+y+z)}$, which will simplify into,
$\dfrac{1}{4}\sqrt{-(x^4+y^4+z^4)+2(x^2y^2+y^2z^2+z^2x^2)}$
Now you can substitute the values to get the required area.
