[问答题]
The diagram shows a parall
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-/ dd x;c1jdzjgram ABCD.
The coordinates of $\mathrm{A}, \mathrm{B} $ and D are $\mathrm{A}(2,3,4), \mathrm{B}(8,5,7)$ and $ \mathrm{D}(4,7,8)$ .
1. 1. Show that $ \overrightarrow{\mathrm{AB}}=\left(\begin{array}{l}6 \\ 2 \\ 3\end{array}\right)$ .
2. Find $\overrightarrow{\mathrm{AD}} .
3. Hence show that $\overrightarrow{\mathrm{AC}}=\left(\begin{array}{l}8 \\ 6 \\ 7\end{array}\right)$ .
2. Find the coordinates of point C .
3. 1. Find $\overrightarrow{\mathrm{AB}} \cdot \overrightarrow{\mathrm{AD}}$ .
2. Hence find B $\hat{A} $D .
4. Hence, or otherwise, find the area of the parallelogram.
