How do I write an ellipse in standard form?

May 22, 2015

${x}^{2} / {a}^{2} + {y}^{2} / {b}^{2} = 1$
In the standard form, $a$ is the radius (distance from the centre of the ellipse to the edge) of the x axis, and $b$ is the radius of the y axis. So, $2 a$ is the length of the x axis, and $2 b$ is the length of the y axis of the ellipse.