Here's the graph of the equation $x^2 + y^2 = 16$. The circle is centered at the origin and has a radius of 4.

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Here are 8 related questions you might find interesting:

1. How would the graph change if the equation were $x^2 + y^2 = 25$?
2. What is the equation of a circle centered at $(3, -2)$ with a radius of 5?
3. How do you find the radius of a circle given its equation in general form?
4. Can you derive the equation of a circle given its center and a point on the circumference?
5. How does the equation change if the circle is translated by a vector?
6. What is the distance formula, and how is it related to the equation of a circle?
7. How do you find the tangent line to a circle at a given point?
8. What are the parametric equations for a circle of radius $r$?

Tip: When graphing circles, always check if the equation is in the standard form $(x - h)^2 + (y - k)^2 = r^2$ to identify the center and radius easily.