Question

help .. The circle below is centered at the origin, and the length of its radius is 12. What is the circle's equation?

Answer 1

well the standard form of the circle equation is

\[(x - h)^2 + (y - k)^2 = r^2\]

(h, k) is the centre and r is the radius

so you have h = 0, k = 0 and r = 12

substitute them and find the answer