posted by Anonymous .
The standard form of a circle is Ax^2+Cy^2+Dx+Ey+F=0.
Write the equation for the circle:
Center (1,2), point on the circle (-2,-1).
Okay, I've always put circles in the form (x-h)^2+(y-k)^2=0. I got this:
then I substitute the point to find the radius:
So the answer I got is
...So what's standard form, and can I change it from my answer to that?
expand and bring all terms to the left side.