Question

Given the equation of the circle find the center and the radius:
(x - 3)2 + (y + 1)2 = 49

Answer 1

(3, -1), 7

Explanation:

To find the center of this circle: compare the given equation

(x - 3)^2 + (y + 1)^2 = 7^2 to the standard equation of a circle with center at (h, k):

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

From this comparison we see that the center is at

h = 3 and k = -1, and also that r must be 7: (3, -1), 7