You can
put this solution on YOUR website!You could go that route, but you'd eventually plug in the given values and evaluate. So why not just skip to this part and make things easier?
So

exactly (where x = 1, y = 2 and z = 1)
If you use the "the decimal value of the square root of 2", then
This means that

which rounds to 339.4
So

(notice how this is approximate and not exact) where x = 1, y = 2 and z = 1