How do you find the center and radius of the circle $x^2+y^2=4$ ?

Question

51563 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-06-13T22:40:57

center $(0,0)$
Radius $=2$

The general equation of a circle is:

$(x-a)^2 + (y-b)^2 = r^2$

Where $(a,b)$ represent the coordinates of the center and $r$ is the radius.
Here in the equation:

$x^2 + y^2 = 4$
$(x - 0)^2 + (y - 0)^2 = 2^2$

Therefore, the circle has :

center $(0,0)$
Radius $r =2$

How do you find the center and radius of the circle x^2+y^2=4 x^2+y^2=4 ?