Equation of a circle!?

Question

Solve.
Find the equation of a circle with center at (-6, 2), passing through the point (-3,6) Write it in center-radius form.

Answer 1

r ² = (- 3 + 6) ² + (6 - 2) ²
r ² = 9 + 16 = 25
(x + 6) ² + (y - 2) ² = r ²
(x + 6) ² + (y - 2) ² = 25

Answer 2

first find the radius of the circle by using the distance formula

Sqrt((-6--3)^2 + (2-6)^2) = Sqrt((-3)^2 + (-4)^2) = Sqrt(25) = 5

since the radius is five the equation of the circle is:

(x+6)^2 + (y-2) = 25

remember the general form of the circle equation for a circle with radius r and center (h, k) is:

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

Answer 3

(x+6)^2 + (y-2)^2 = 25