Answer
equation in standard form: $(x-2)^2+(y-1)^2=4$
center: $(2, 1)$
radius = $2$ units
Work Step by Step
The standard equation for a circle with radius $r$ and centre $(h,k)$ is: $(x-h)^2+(y-k)^2=r^2$.
The distance between the point on the circle $(0, 1)$ and the center $(2, 1)$ is $2$ units.
The given circle has $r=2$ and has its center at $(2, 1)$.
Thus, the standard form of the circle's equation is:
$(x-2)^2+(y-1)^2=2^2\\
(x-2)^2+(y-1)^2-4$