Circle

Definition

A circle is the set of points that are a fixed distance r, called the radius, from a fixed point (x, y), called the center. It can be thought of as a special case of an ellipse when $a^{2}=b^{2}$

Algebraic Expression

The equation for the circle of radius r centered at (0, 0) is $x^{2}+y^{2}=r^{2}$

If you want a circle centered at (h, k) replace x with (x - h) and y with (y - k)

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