1. The problem is to simplify or understand the expression $\sqrt{x^2 + 100}$.\n\n2. The square root function $\sqrt{\cdot}$ returns the non-negative value whose square is the argument inside. Here, the expression inside the root is $x^2 + 100$.\n\n3. Note that $x^2$ is always non-negative for any real $x$, and $100$ is positive, so $x^2 + 100$ is always positive.\n\n4. Since $x^2 + 100$ cannot be factored into a perfect square, the expression $\sqrt{x^2 + 100}$ cannot be simplified further algebraically.\n\n5. Therefore, the simplified form remains $\sqrt{x^2 + 100}$.\n\n6. This expression represents the distance from the point $(x,0)$ to the point $(0,10)$ on the Cartesian plane, if you think geometrically.