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Multiple Choice
Give the center and radius of each circle and graph.
A
; Center:
B
; Center:
C
; Center:
D
r=2; Center: (−2,3)
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Verified step by step guidance
1
Identify the center of the circle by locating the point equidistant from all points on the circle. From the graph, the center is at the point \((-2, 3)\).
Determine the radius by measuring the distance from the center to any point on the circle. For example, the point \((-2, 5)\) lies on the circle, so calculate the distance between \((-2, 3)\) and \((-2, 5)\).
Use the distance formula or simply count the units on the graph since the points are aligned vertically: the radius \(r\) is the difference in the y-coordinates, which is \$5 - 3$.
Write the equation of the circle in standard form: \(\left(x - h\right)^2 + \left(y - k\right)^2 = r^2\), where \((h, k)\) is the center and \(r\) is the radius.
Substitute the center \((-2, 3)\) and the radius \(r\) into the equation to get \(\left(x + 2\right)^2 + \left(y - 3\right)^2 = r^2\).