$\"\"$

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The endpoints of a diameter at $\"\"$

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Midpoint = $\"\"$ .

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Substitute $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ $\"\"$

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Find the radius, apply distance formula.

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$\"\"$

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Substitute $\"\"$ .

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$\"\"$

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$\"\"$

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Evaluate powers: $\"\"$ .

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$\"\"$

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$\"\"$

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The radius of the circle is $\"\"$ , So $\"\"$ . $\"\"$

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The equation of a circle with center $\"\"$ and radius r units is $\"\"$ .

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Substitute $\"\"$ .

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$\"\"$

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$\"\"$ $\"\"$

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The equation of the circle is $\"\"$ .