Question

The circle below is centered at (3, 1) and has a radius of 2. What is its
equation?

Answer 1

B.
`(x-3)^2+(y-1)^2=4`

Explanation:

Standard equation of a circle with a center at C=(3,1) and radius 2 is:

`(x-3)^2+(y-1)^2=4`

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

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

In this example h=3, k=1 and r=2, so after substituting into above formula we have:

`(x-3)^2+(y-1)^2=2^2\\(x-3)^2+(y-1)^2=4`

Thanks.