Question

how do you determine the equation of a circle given 3 pts?

Answer 1

determine it from a polynomial? what do you mean specifically?

Answer 2

Find the equation of the circle which passes through the points (-1,-1), (-8,-8), and (-7,-9)

Answer 3

(x - h)^2 + (y - k)^2 = r^2

plug those points in for x and y to solve for h,k, and r.

Answer 4

so as sourwing said, you grab the Circle equation
plug in the 1st pair (-1, -1)
then you do the same for the 2nd pair
and the same for the 3rd pair

then you'd end up with a "system of equations of 3 variables"

from which you'd get "h", "k", and "r"