The area of the parallelogram whose sides

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The area of the parallelogram whose sides are represented by the vectors $\hat j + 3\hat k$ and $\hat i + 2\hat j - \hat k$ is

A

$\sqrt {61} $ sq.unit

B

$\sqrt {59} $ sq.unit

C

$\sqrt {49}  $ sq.unit

D

$\sqrt {52} $ sq.unit

The area of the parallelogram whose sides are represented by the vectors $\hat j + 3\hat k$ and $\hat i + 2\hat j - \hat k$ is

$\vec A = \hat j + 3\hat k$,$\vec B = \hat i + 2\hat j - \hat k$

$\vec C = \vec A \times \vec B = \left| {\,\begin{array}{*{20}{c}}{\hat i}&{\hat j}&{\hat k}\\0&1&3\\1&2&{ - 1}\end{array}\,} \right|$$ = - 7\hat i + 3\hat j - \hat k$

Hence area = $|\vec C| = \sqrt {49 + 9 + 1} = \sqrt {59} \,sq\,unit$