• 55. One of the following equations represents the ellipse shown below in the standard (x,y) coordinate plane. Which one?
    Choice D

    The equation of an ellipse in standard form follows:

    $$ \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1 $$

    To find the center of the ellipse:

    The x coordinate of the center will be the same as (2,2) and (2,-8), 2, which makes h = 2;

    The x coordinate of the center will be the same as (-1,-3) and (5,-3), -3, which makes k = -3;

    The center is (2,-3).

    The distance between the center (2,-3) and (5,-3) is 5-2=3, which makes a = 3;

    The distance between the center (2,-3) and (2,2) is 2-(-3)=5, which makes b = 5;

    Therefore the ellipse equation is:

    $$ \frac{(x-2)^2}{3^2}+\frac{(y+3)^2}{5^2}=1 $$

    $$ => \frac{(x-2)^2}{9}+\frac{(y+3)^2}{25}=1 $$