What is the standard form of the equation of the circle in the graph?

(x + 3)^2 + (y + 3)^2 =3
x^2 + y^2 = 9
x^2 + y^2 = 3
(x + 3)^2 + (y + 3)^2 =9

Question

What is the standard form of the equation of the circle in the graph?
 	
	(x + 3)^2 + (y + 3)^2 =3
	x^2 + y^2 = 9
	x^2 + y^2 = 3
	(x + 3)^2 + (y + 3)^2 =9

anonymous · Answer

attachment

agent0smith · Answer

It's center is at (0, 0) which means it's of the form 
x^2 + y^2 = r^2
so you can already eliminate two answers.

So you need to find the radius of the circle... find the distance from the center to a point on the circle.

agent0smith · Answer

Once you find the radius, square it, and you'll have the equation x^2 + y^2 = r^2 and can match it to an answer (the r in that equation is radius).

anonymous · Answer

how do you find the radius?

anonymous · Answer

never mind. i think the answer is b.

agent0smith · Answer

You find the radius as i said above. Count how many units you have to go across, from the center of the circle, to the edge of the circle.