Question

Which is an equivalent equation solved for y?

Answer 1

X and y are the half length of the largest and smallest diameter of the ellipse.
Area of the Ellipse , a = πxy
To find: Equivalent Equation for y.

Consider,
a = πxy
πxy = a
(πx)y = a
transpose πx to RHS,

y = a ÷ ( πx )
Hope this helps!