Chapter 9.3, Problem 8CYU

To determine

To Find: The center and radius of the circle then graph the circle.

Answer to Problem 8CYU

  $\begin{array}{l}(h,k)=(0,0)\\ r=4\end{array}$

Explanation of Solution

Given: $x^2+y^2=16$

Equation of the circle

  ${(x-h)}^2+{(y-k)}^2=r^2\mathrm{....}(i)$

We can write the equation $x^2+y^2=16$ as

  $\begin{array}{l}{x}^2+y^2=16\\ $ {(x-0)}^2+{(y-0)}^2=4^2$\end{array}$

Comparing with $(i)$

We get

  $\begin{array}{l}(h,k)=(0,0)\\ r=4\end{array}$

Where $(h,k)$ is the center of the circle and $r$ is the radius of the circle

The graph of the circle is