Question

what is the center and radius of the circle with the equation x^2+y^2=81

Answer 1

so the basic formula for circles is:
\[(x-h)^2+(y-k)^2=r^2\]

Answer 2

the center of a circle is h,k and its radius is r

Answer 3

in ur case h and k are both 0, so the center is at (0,0) and the radius is 9

Answer 4

Thanks

Answer 5

no problem