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A circle has an area of approximately 78.5 square units. If the center of the circle is at (2,4). Which of the following points is on the circle? (-6, 4) (2, -1) (-4, -4) (2, -9)

Donald Ward

in Geography

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Eric Morgan on March 4, 2018

The answer is (2, -1)The area of the circle is:A = r2nWe knowA = 78.5 π = 3.1478.5 = r2 * 3.14r2 = 78.5 : 3.15r2 = 25r = √25 = 5the standard form of the equation of a circle is:(x - h)2 + (y - k)2 = r2We have:(2, 4)⇒ h = 2 k = 4r = 5(x - h)2 + (y - k)2 = r2(x - 2)2 + (y - 4)2 = 52(x - 2)2 + (y - 4)2 = 25Now, we will replace all the options:(-6, 4):(-6 - 2)2 + (2 - 4)2 = 25(-8)2 + (-2)2 = 2564 + 4 = 2568 = 25INCORRECT(2, -1)(2 - 2)2 + (-1 -4)2 = 2502 + (-5)2 = 250 + 25 = 2525 = 25CORRECT


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