9 With respect to the origin \(O\), the points \(A , B\) and \(C\) have position vectors given by
$$\overrightarrow { O A } = \left( \begin{array} { r }
2
1
- 3
\end{array} \right) , \quad \overrightarrow { O B } = \left( \begin{array} { l }
0
4
1
\end{array} \right) \quad \text { and } \quad \overrightarrow { O C } = \left( \begin{array} { r }
- 3
- 2
2
\end{array} \right)$$
- The point \(D\) is such that \(A B C D\) is a trapezium with \(\overrightarrow { D C } = 3 \overrightarrow { A B }\).
Find the position vector of \(D\).
- The diagonals of the trapezium intersect at the point \(P\).
Find the position vector of \(P\).
\includegraphics[max width=\textwidth, alt={}, center]{9da6c2ac-31aa-4063-88b9-e15e38bedd8a-13_2725_35_99_20} - Using a scalar product, calculate angle \(A B C\).