Write an equation of a circle centered at (3,-7) that passes through (15,13)

Answer 1

(x-3)^2 + (y+7)^2 = r^2

plug in the point to solve for r

(15-3)^2 + (13+7)^2 = r^2

144 +400 = r^2

r^2 = 544

r=sqr544= radius

the equation of the circle with given center and point is

the radius = sqr544 = 2sq136 = 4sqr34 = about 23.3 = r

(x-3)^2 + (y+7)^2 = 544

Answer 2

(x-3)^2 + (y+7)^2 = R^2

(15-13)^2 + (13+7)^2 = R^2

2^2 + 20^2 = R^2

4+400 = 5^2

404 = r^2

r = 2*sqrt(101)

(x-3)^2 + (y+7)^2 = 404