Question #N790
The equation $(x+2)^2 + (y-1)^2 = 4$ defines a circle in the $xy$-plane. What is the radius of this circle?
A. 1
B. 2
C. 4
D. 8
Correct Answer is: B
The standard form of the equation of a circle with center $(h,k)$ and radius $r$ is $(x-h)^2 + (y-k)^2 = r^2$. In this case, the equation of the circle is $(x+2)^2 + (y-1)^2 = 4$, which can be rewritten as $(x-(-2))^2 + (y-1)^2 = 2^2$. Therefore, the radius of the circle is 2.