Solution
- The endpoints of the diameter are P(-6, -11) and Q(4, 7).
- The formula for the equation of a circle is:

- To find the radius of the circle, we need to find the coordinate of the center and then apply the distance formula to find the length of the radius.
- That is,

- Applying the midsegment formula given above, we can find the coordinates of the center of the diameter as follows:

- Thus, the coordinate of the center of the circle is:

- Now that we have the coordinates of the center, we can find the distance from the center to any of the points given to us that lie on the circumference of the circle using the distance formula given above. This will give us the radius.
- Thus, we have:

- Thus, we can write the equation of the circle as follows:

The circle is depicted below: