What is the center and radius of a circle that has a diameter with endpoints (-9,-6) and (-1,0)
That's very close to being trivial! The center of the circle is at the midpoint of any diameter. And the midpoint of the line segment between two points is the average of the two points. The center of the circle is the midpoint of the line between (-9, -6) and (-1, 0): ((-9+(-1))/2, (-6+0)/2)= (-10/2, -6/2)= (-5, -3). And the radius is the distance from (-5, -3) to either of the given points.
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