The area of the quadrilateral $ABCD$ with vertices $A(2, 1, 1)$,$B(1, 2, 5)$,$C(-2, -3, 5)$,and $D(1, -6, -7)$ is equal to

The area of a parallelogram whose adjacent sides are $i - 2j + 3k$ and $2i + j - 4k$ is:

Let $\vec{a}$ and $\vec{b}$ be two vectors of length $\sqrt{2}$ such that $|\vec{a} + \vec{b}| = \sqrt{5}$. If $\vec{c} = \vec{a} + 2\vec{b} + 2(\vec{a} \times \vec{b})$,then $|\vec{c}|$ is

The sine of the angle between the two vectors $3i + 2j - k$ and $12i + 5j - 5k$ will be

Using vectors,prove that parallelograms on the same base and between the same parallels are equal in area.

Let $\vec{a}$ and $\vec{b}$ be two vectors such that $|\vec{b}|=1$ and $|\vec{b} \times \vec{a}|=2$. Then $|(\vec{b} \times \vec{a})-\vec{b}|^2$ is equal to