Thanks.

I think I can work out the focus points from there.
However, I thought when stretched it into an ellipse and brought points to the edge of the rectangle the circle was drawn on that it would break the plane so I could get rid to the extra bit of rectangle.
In real world terms what I'm trying to do is replicate the "cut off" at the upper front corner of the teardrop. I started with my rectangle (the profile view of the TD) and now I want to cut away the extra upper/forward part of that to end up with the elliptical front that the TD has.
If this is an easy answer thanks in advance; if it's just too much tying I'll understand!

This isn't something I
have to do; I'd just like to take the 2D drawings I have and see what it might look like in the Sketchup 3D world.