Question

A circle is shown on the coordinate plane below.

What is the equation of this circle?

x2 + (y + 1)2 = 4

x2 + (y – 1)2 = 2

x2 + (y + 1)2 = 2

x2 + (y – 1)2 = 4

Answer 1

the center is at (0,1) and the radius is 2.
general format of a circle:
(x-h)2 + (y-k)2 = r2
so this gives us:
x2 = (y-1)2 = 4
So the answer is D.

Answer 2

oh ok, thank you :)