## anonymous one year ago what is the radius of a circle with the equation x^2+y-3^2 =21

1. Ac3

The formula for a circle is x^2+y^2=r^2, therefore it's already set up for you. Not it's not 21 Here I'm gonna go with the sqrt(21) for the radius. Unless 21 is supposed to be squared in that case it's just 21.

2. zzr0ck3r

$$x^2+(y-3)^2=21\\ (x+0)^2+(y-3)^2=(\sqrt{21})^2$$

3. zzr0ck3r

You should be able to complete it from here?

4. wolf1728

Is that equation written exactly as the problem states or should it be: x^2+(y-3)^2 =21

5. anonymous