Hi there!
The standard form of the equation of a circle is:[tex](x-a)^{2} + (y-b)^{2} = r^{2} [/tex]
With (a, b) representing the centre and r representing the radius of the circle. Since the centre of the circle is (0, 0) and the radius is 3, we get the following equation:
[tex](x-0)^{2} + (y-0)^{2} = 9 \\ x^{2} + y^{2} = 9[/tex]
~ Hope this helps you!
