What is the equation of the circle with a center at (2 ,1 ) and a radius of 3 ?

1 Answer
Jan 26, 2016

(x-2)^2+(y-1)^2=9

Explanation:

The standard form of a circle with a center at (h,k) and a radius r is

(x-h)^2+(y-k)^2=r^2

Since the center is (2,1) and the radius is 3, we know that

{(h=2),(k=1),(r=3):}

Thus, the equation of the circle is

(x-2)^2+(y-1)^2=3^2

This simplifies to be

(x-2)^2+(y-1)^2=9