Question

4) Center: (3,7) Radius: 9

Answer 1

The equation of the circle with center (h,k) and radius r is:

$(x-h)^2+(y-k)^2=r^2$

In this case we have the following:

$\begin{gathered} (h,k)=(3,7) \\ r=9 \\ \Rightarrow(x-3)^2+(y-7)^2=(9)^2 \end{gathered}$

therefore, the equation of the circle with center (3,7) and radius 9 is:

$(x-3)^2+(y-7)^2=81$