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:

The general circle equation is

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

where r is the radius.

Since we know all the information just plug it in the equation above.

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

Simplify 3 squared.

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