If a vector $\vec{r}$ makes equal angles with the axes $OX, OY,$ and $OZ$,find the total number of such vectors $\vec{r}$.

If $ABCDEF$ is a regular hexagon with $\vec{AB} = \vec{a}$ and $\vec{BC} = \vec{b}$,then $\vec{CE}$ equals to

If $a, b$ and $c$ are three vectors such that $|a|=|b|=2$,$a \cdot b=2$ and $a+b+c=0$,then $|c|$ is equal to

Let $3 \hat{i}+\hat{j}-\hat{k}$ be the position vector of a point $B$. Let $A$ be a point on the line which is passing through $B$ and parallel to the vector $2 \hat{i}-\hat{j}+2 \hat{k}$. If $|\overrightarrow{B A}|=18$, then the position vector of $A$ is

The triad $(x, y, z)$ of real numbers such that $(3 \hat{i}-\hat{j}+2 \hat{k})=(2 \hat{i}+3 \hat{j}-\hat{k}) x+(\hat{i}-2 \hat{j}+2 \hat{k}) y+(-2 \hat{i}+\hat{j}-2 \hat{k}) z$ is

$A$ unit vector in $XY$-plane making an angle $45^{\circ}$ with $\hat{i}+\hat{j}$ and an angle $60^{\circ}$ with $3\hat{i}-4\hat{j}$ is