Verified answer

The standard equation of a circle with center at point (h,k) is (x − h)² + (y − k)² = r². Since you only have x² + y², the circle's center is located at point (0,0). Its radius would be √5.

The full equation of a circle is this:

(X - H)² + (Y - K)² = R²

R is the radius

H & K are the X & Y coordinates of the center of the circle.

Thus from your equation you have a circle centered at the Origin (0, 0), with a radius of ~2.23.

The X & Y in the equation itself are positions on the circle itself

the graph of this circle is centered at the origin because the x and y do not have a number in front of them (ex. 3x^2). the radius is the square root of 5. :)