Conic sections - Ellipse
An ellipse can be defined as the shape created when a plane intersects a cone at an angle to the cone's axis. It is one of the four conic sections. (the others are an circle, parabola and hyperbola).
In the above figure, there is a
that cuts through a
When the plane is parallel to the cone's base, the
of the cone and plane is a
But if the plane is tilted, the intersection becomes an
In the the figure above, as you drag the plane, you can create both a circle and an ellipse. The shape on the left shows the view that is perpendicular to the plane - as if you were looking straight down on the plane.
If you were to keep tilting the plane until it is parallel to the cone sides, the intersection would become a
If you kept going until the plane was vertical, the intersection becomes a
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