### Home > PC3 > Chapter 11 > Lesson 11.1.3 > Problem11-39

11-39.

Describe the graph of:

1. $x^2 + y^2 = 16$

The equation is in the form $x^{2} + y^{2} = r^{2}$. What is the shape of the curve?

This is the graph of a circle with center (_, _) and radius _.

1. $r = 4$

This curve has a constant radius of $4$.