#### Answer

$x^{2} + y^{2} = 12.25$

#### Work Step by Step

The radius is the diameter divided by two, or $\frac{7}{2} = 3.5$.
The general form of a circle is $r^{2} = (x - h)^{2} + (y - k)^{2}$ where $r$ is the radius of the circle and the ordered pair $(h, k)$ is the center of the circle.