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Equation of a circle
You know that a circle can be viewed as the set of all points that whose distance from the center is equal to the radius. In this tutorial, we use this information and the Pythagorean Theorem to derive the equation of a circle.
Sal finds the center and the radius of the circle whose equation is (x+3)^2+(y-4)^2=49.
Find the center and radius of a circle given the equation in standard form.
Sal finds the center and the radius of a circle whose equation is x^2+y^2+4x-4y-17=0, and then he graphs the circle.
Find the center and radius of a circle given the equation in expanded form.