Question

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

Answer 1

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

Explanation:

Answer 2

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

Explanation:

The equation of a circle is
`(x-h)^(2) +(y-k)^(2) = r^(2)` in which (h,k) is the center of the circle and r is the radius of the circle. (x,y) can represent any point on the circle but when the equation is written standardly, it is left as (x,y).

Because (1,2) is (h,k) it will be inputted as:

`(x-1)^(2) + (y-2)^(2)`

The radius is 3 but in the equation it must be squared.

3 x 3 is 9, so the full equation is:

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