#### Answer

$$\sqrt{24}$$

#### Work Step by Step

There are two ways to graph a function. First of all, we could recognize, based on the form that the equation is in, what the shape and location of the graph will be. However, it can often times be easier to plot points in order to see the shape of the graph, allowing us to create the overall graph. We see that the radius of the circle is:
$$\sqrt{24}$$