Answer
See below
Work Step by Step
From part b, we found:
$a=36.5\\c=7.5$
Find b: $c^2=a^2-b^2\\7.5^2=36.5^2-b^2\\b^2=36.5^2=7.5^2=1276$
Obtain: $\frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1\\\frac{(x-0)^2}{36.5^2}+\frac{(y-0)^2}{1276}=1\\\frac{x^2}{1332}+\frac{y^2}{1276}=1$