$\frac{x^2}{16} - \frac{y^2}{9} = 1$

$\frac{x^2}{16} - \frac{y^2}{36} = 1$

$\frac{x^2}{16} - \frac{y^2}{4} = 1$

$\frac{x^2}{4} - \frac{y^2}{16} = 1$