Question
Question: If \(\mathbf{a} = - 3\mathbf{i} + 7\mathbf{j} + 5\mathbf{k},\) \(\mathbf{b} = - 3\mathbf{i} + 7\math...
If a=−3i+7j+5k, b=−3i+7j−3k, c=7i−5j−3k are the three coterminous edges of a parallelopiped, then its volume is
A
108
B
210
C
272
D
308
Answer
272
Explanation
Solution
Volume $= \left| \begin{matrix}
- 3 & 7 & 5 \
- 3 & 7 & - 3 \ 7 & - 5 & - 3 \end{matrix} \right|$
=−3(−21−15)−7(9+21)+5(15−49)
=180−210−170=272.