Algebra
posted by Bree on .
Write the equation of the circle. Center at (4,2) and the circle passes through the point (1,1).
Please help!

recall the equation of a circle with centre (h,k) and radius r is
(xh)^2 + (yk)^2 = r^2
so
(x4)^2 + (y2)^2 = r^2
but (1,1) lies on it
sub x=1 and y=1 to find r^2
let me know what you get.