Question 342428
Find the equation of a circle satisfying the condition given. Sketch the graph:

diameter has endpoints (5,1) and (5,7)
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Both x values are 5, so that makes it easier.
The midpoint is the center of the circle, at (5,4)
A circle with its center at (h,k) and radius r is:
{{{(x-h)^2 + (y-k)^2 = r^2}}}
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The radius is the distance to either point, = 3
--> {{{(x-5)^2 + (y-4)^2 = 9}}}
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There's not always a formula to use.  You have to figure it out.