Coordinate Geometry - Equation of a Circle (GRE)

These lessons are part of a series of lessons for the quantitative reasoning section of the GRE revised General Test. In these lessons, we will learn how to graph and write the equations of circle.

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Equation Of Circle Tutorial

Equation of a Circle

The graph of an equation of the form (xa)2 + (yb)2 = r2 is a circle with its center at the point (a, b) and with radius r.

This video looks at using equations of circles to find the center and the radius of a circle to graph it, as well as, writing an equation for a circle, given the center and radius, or a point on the circle. It includes four examples.

This video shows how to graph and write equations of circles.

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.
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