Q: The ellipse $\displaystyle D$ has equation $\displaystyle \frac{x^2}{25} + \frac{y^2}{9} = 1$ and the ellipse $\displaystyle E$ has equation $\displaystyle \frac{x^2}{4} + \frac{y^2}{9} =1$. The point $\displaystyle S$ is a focus of $\displaystyle D$ and the point $\displaystyle T$ is a focus of $\displaystyle E$. Find the length of $\displaystyle ST$.

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As the major axis for ellipse $\displaystyle E$ is the y-axis, does that mean that the focus lies on that axis too? Also, can someone draw a picture showing me what it is asking for? Thanks in advance.