\begin{definition}[Definition:Conic Section/Intersection with Cone/Tilting Angle]
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Let $C$ be a double napped right circular cone whose base is $B$.
Let $D$ be a plane which intersects $C$.
Let $D$ be inclined at an angle $\phi$ with the axis of $C$.
Let $K$ be the '''conic section''' formed by the intersection of $C$ with $D$.
The inclination $\phi$ of the slicing plane with the axis of $C$ is known as the '''tilting angle''' of $D$ for $K$.
\end{definition}