Question

from the equation of a circle (x-4)^2+(y-8)^2=64, which are the center and the radius?

Answer 1

centre (4,8) and radius=sqrt(640=8 units

Answer 2

(x-a)^2+(y-b)^2=r^2
(a,b) is the center
r is the radius

Answer 3

for centre (h,k) and raius r
the eq is (x-h)^2 +(y-k)^2=r^2

Answer 4

hrmm... what's the answer? o.o

Answer 5

Compare your equation:
\[(x-4)^{2}+(y-8)^{2} = 64\]
to the standard form:
\[(x-h)^{2} +(y-k)^{2}=r ^{2}\]
Where, as matricked and wacsam said, the center is (h, k) and the radius is r.