Magnitude of a Vector

Let's say that in fluid mechanics, we have this kind of submerged surface, and this is the free surface. And I'm interested in finding the magnitude of the force, which is a vector that is exert on the submerged surface. So, I'm going to have a combined force like this, right? But if I'm given, let's say, the x F of x and F of z components, all I have to do is—you know, so it's fairly simple—that you already notice is summation of F of x square plus F of y square plus F of z square, and I take the square root of it all. Okay, so that's going to give me the magnitude of the vector.