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Question 557944: write the standard form of the equation of the circle that passes through the point at (2, -2) and has its center at (-2, 3).
Answer by Edwin McCravy(20060) (Show Source):
You can put this solution on YOUR website! write the standard form of the equation of the circle that passes through the point at (2, -2) and has its center at (-2, 3).
The standard form of a circle is
(x - h)² + (y - k)² = r²
where the center is (h,k) and the radius is r
We know the center (h,k) = (-2,3), so h = -2 and k = 3.
So we can fill those in
(x - h)² + (y - k)² = r²
(x - (-2))² + (y - (3))² = r²
(x + 2)² + (y - 3)² = r²
We plot the center and the point the circle goes through:
To find the radius, some people use the distance formula, but
you can just substitute the point (x,y) = (2,-2) into the equation
(x + 2)² + (y - 3)² = r²
(2 + 2)² + (-2 - 3)² = r²
4² + (-5)² = r²
16 + 25 = r²
41 = r²
Of course the radius is but r² = 41 is what we need
to finish the standard form:
(x + 2)² + (y - 3)² = 41
Edwin
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