SOLUTION: how do you find the center-radius form of the equation of a circle with center (4,-7) and tangent to the y-axis?

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Question 184089: how do you find the center-radius form of the equation of a circle with center (4,-7) and tangent to the y-axis?
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


The equation of a circle with center at (h,k) and radius r is:



You are given the center, (4,-7), and that the circle is tangent to the y-axis. That means the radius is the distance from the y-axis to the center, or simply the value of the x-coordinate of the center, namely 4. Substituting:






T is the point of tangency.

John