The Standard Equation of a Circle

In order to determine the standard equation of a circle, you will need to use your knowledge of circles and your skills in the coordinate plane. In this video, you will learn how to derive the formula for the standard equation of a circle using the Pythagorean Theorem. Click the player button to begin.
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Determining the Equation of a Circle Given the Coordinates of the Center and a Point on the Circle

Determining the equation of a circle when given the coordinates of the center and a point on a circle requires your knowledge of the standard equation of a circle. In this video, you will learn to find the center and the radius of a circle. This will require you to use the midpoint formula, since the center of a circle is equidistant from two given points. Click the player button to begin.
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Determining the Equation of a Circle Given the Coordinates of the Endpoints of a Diameter

To determine the equation of a circle given the coordinates of the endpoints of the diameter, your knowledge of the standard equation of a circle and your knowledge of coordinate methods will be very helpful. In this video, you will learn how to find the equation of a circle with endpoints of the diameter by finding both the center and the radius. Click the player button to begin.
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Identifying Points that Lie on a Circle

Your knowledge of the standard equation of the circle and your knowledge of coordinate methods will help you identify points that lie on a circle. In this video, you will learn how to identify points that lie on a circle. Click the player button to begin.
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Equation of a Circle Review

Now that you have explored the equation of a circle, review your knowledge in this interactivity. Click the player button to get started.