Question

What is the equation of a circle whose center is `(0, -7)` and whose radius is `sqrt8`?

Answer 1

See the solution process below:

Explanation:

From: https://www.mathsisfun.com/algebra/circle-equations.html

The equation for a circle is:

`(x - color(red)(a))^2 + (y - color(red)(b))^2 = color(blue)(r)^2`

Where `(color(red)(a), color(red)(b))` is the center of the circle and `color(blue)(2)` is the radius of the circle.

Substituting the values from the problem gives:

`(x - color(red)(0))^2 + (y - color(red)(-7))^2 = color(blue)(sqrt(8))^2`

`x^2 + (y + color(red)(7))^2 = 8`