Give the equation for the ellipse with foci at (0, +/-2) and semi-major axis 3.

I find that:

a = 3

b = sqrt(5)

c = +/- 2

Thus by the standard equation of the ellipse:

x^2/a^2 + y^2/b^2 = 1

I get:

x^2/9 + y^2/5 = 1

However, the correct answer is supposed to be:

x^2/5 + y^2/9 = 1

What is wrong with my approach?