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Review: Circle in the Coordinate Plane
Explanation
To find the circumference of this circle, we need its
radius. And the radius is the distance from its center to any point on the
circle, so the radius is the distance from (-1 ,-3) to (4,2).
This distance is computed with the distance formula, which
is essentially the Pythagorean Theorem. The sides of the triangle are the x and y distances, 5 and 5, so the distance is 
.
The radius of the circle is 
,
so the circumference is 
.
The correct answer is (B).
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