Factoring and Ellipses: How to Solve for Width?

[runicle]

I'm trying to put this into factored form help me out and help me with ellipses I don't know what to do... Would i have to place the C that i solved into $$a^2 = 10^2 + 25.4^2$$ http://s65.photobucket.com/albums/h237/runicrice/?action=view&current=scan.jpg

 

[runicle]

My work is in the url...

 

[Astronuc]

If I read this correctly, the question is "What is the width of when the height is 10 units above the origin," which is somewhat of a confusing question.

10 units above the origin is point (0,10) which has x=0, and y=10.

Is the height, h = the vertical distance between the x-axis and the center of the ellipse?

Anyway, is the width considered the major axis or minor axis?

One can solve for either.