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Find the length of the radius of a circle whose center is at (3,4) and passes through (-3, -4)

User Doan
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2 Answers

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The length of the radius is given by the Pythagoras formula which take the radius as the hypotenuse.

radius =
\sqrt{[x_(1)- x_(2)]^2+[ y_(1) - y_(2)]^2 }
radius =
√((3--3)^2+(4--4)^2)
radius =
√(6^2+8^2)
radius =
√(36+64)
radius =
√(100)
radius = 10

Find the length of the radius of a circle whose center is at (3,4) and passes through-example-1
User Eduard Uta
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The equation of a circle is: (x - xo)^2 + (y - yo)^2 = r^2

Where xo and yo are the coordinates of the center = (3,4).

r is the radius of the circle and you can find it using the equation of the distance between the point (-3,-4) and the center (3,4):

r^2 = (-3 -3)^2 + (-4 - 4)^2 = 6^2 + 8^2 = 36 + 64 = 100.

=> r = √100

=> r = 10

Answer: r = 10
User Embattled Swag
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