# Equation Of A Circle

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question
What is the center of a circle represented by the equation (x+9)2+(yβ6)2=102?
(β9,6)
question
What is the center of a circle whose equation is x2 + y2 - 12x - 2y + 12 = 0?
(6, 1)
question
Does the point (2,root of 6) lie on the circle shown? Explain.
No, the distance from (0, 0) to (2, root of 6) is not 3 units.
question
Does the point (1, StartRoot 7 EndRoot) lie on the circle shown? Explain.
Yes, the distance from (-2, 0) to (1, ) is 4 units.
question
What is the radius of a circle whose equation is x2+y2+8xβ6y+21=0?
2 units
question
In the diagram, a circle centered at the origin, a right triangle, and the Pythagorean theorem are used to derive the equation of a circle, x2 + y2 = r2. If the center of the circle were moved from the origin to the point (h, k) and point P at (x, y) remains on the edge of the circle, which could represent the equation of the new circle?
(x - h)2 + (y - k)2 = r2
question
Which equation represents a circle with a center at (-3, -5) and a radius of 6 units?
(x + 3)2 + (y + 5)2 = 36
question
Which point is on the circle centered at the origin with a radius of 5 units?
(2, β Μ21)
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What is the center of a circle whose equation is x2 + y2 + 4x - 8y + 11 = 0?
(-2, 4)
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Which equation represents a circle that contains the point (-5, -3) and has a center at (-2, 1)?
(x + 2)2 + (y - 1)2 = 25
question
Which equation represents a circle with the same center as the circle shown but with a radius of 2 units?