Question 189346
Since we know the center point and one point on the circle, we can find the distance between the center and that point.  The answer will yield the radius.
Once we know the radius, the diameter is twice the radius.

Let d = distance between the two given points.

d = sqrt{(2 - (-4))^2 + (-5 - 3)^2}

d = sqrt{36 + 64}

d = sqrt{100}

d = 10

Our radius is a whole number: 10

So, there is no need to round off.

radius = 10

The diameter is twice is the radius and so it is 20.

I hope this helps.