Question

Find the equation of a circle with a center at (7, 2) and a point on the circle at (-2, -5).

Answer 1

Answer:2nd one

Explanation:

Answer 2

`(x-7)^2+(y-2)^2=130`

Explanation:

The standard form of a circle is

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

where x and y are points on the circle, h and k are the center, and r is the radius. We have what we need to fill in everything but the radius, but we will solve for that like this:

`(-2-7)^2+(-5-2)^2=r^2`

Simplifying gives you

`(-9)^2+(-7)^2=r^2`

and

`81+49=r^2`

so
`r^2=130`

That means the equation for this circle is

`(x-7)^2+(y-2)^2=130`