The template for circle equations is: [tex] { (x - h)}^{2} + {(y - k)}^{2} = {r}^{2} [/tex] where the center is (h, k).
So actually you don't need Pythogarean theorem while constructing the equation.
The given center is (−2, −3), and radius is 3. When we plug those in: [tex] {(x - ( - 2))}^{2} + {(y - ( - 3))}^{2} = {3}^{2} => {(x + 2)}^{2} + {(y + 3)}^{2} = 9[/tex] is your circle equation.
