Answer:
x^2 + y^2 = 25
Step-by-step explanation:
The standard form of a circle equation is:
(x - h)^2 + (y - k)^2 = r^2
where (h, k) is the center and r is the radius.
We can see that the center is (0, 0) by looking at the graph, and the radius is 5 because it is marked. Plugging these in we get:
x^2 + y^2 = 25
