Use the midpoint formulas to find the midpoint of the diameter which is the center of the circle. Use the distance formal to find the distance from the center to either endpoint of the diameter to find the measure of the radius.
Then the equation of the circle is:
Where is the center of the circle and is the radius of the circle.
Hint: Use this form of the distance formula: because you don't actually need you need
You can put it into whatever form you like after that.
John
My calculator said it, I believe it, that settles it
