Question

what's the equation of a circle? is there a specific one?

Answer 1

For a circle with a radius of r that is centered at (h, k), its equation is:\[(x-h)^2 + (y-k)^2 = r^2\]

Answer 2

So for example, a circle with a radius of 4 and that has a center at (3,2), its equation would be\[(x - 3)^2 + (y - 2)^2 = 16\]