Respuesta :

the center is at (0,0) so the equation will be like

x^2 + y^2 = r^2      where r = radius of the circle.

from the diagram you can see that r = 4

answer is x^2 + y^2 = 16
irspow
The standard equation of a circle is:

(x-h)^2+(y-k)^2=r^2, where (h,k) is the center of the circle and r is the radius.

The circle in the diagram is centered at (0,0) and has a radius of 4 so:

x^2+y^2=16