SOLUTION: Find the radius of the circle. {{{x^2 + y^2 + 4x - 16y + 19 = 0}}}

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Find the radius of the circle. {{{x^2 + y^2 + 4x - 16y + 19 = 0}}}      Log On


   

Question 876478: Find the radius of the circle.
x%5E2+%2B+y%5E2+%2B+4x+-+16y+%2B+19+=+0
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
Need to Know: Completing Square
(x+2)^2 + (y-8)^2 = -19 + 4 + 64 = 49
(x+2)^2 + (y-8)^2 = 49 (which is r^2)
r = 7
(positive root only for unit measure)