This circle is centered at the origin, and the length of its radius is 2. What iS
the circle's equation?

Answer:
Step-by-step explanation:
If the center of the circle is at the origin, the general formula for the circle is
x^2 + y^2 = r^2.
Since r = 2 units in this particular problem, the equation of the circle is:
x^2 + y^2 = 2^2, or x^2 + y^2 = 4