The projections of a line on the coordinate axes are $2, 3, 6$. Then the length of the line is

The direction cosines of the supporting line of the vector $\hat{i}+\hat{j}-2 \hat{k}$ are

If the direction cosines of two lines are such that $2l + m + 2n = 0$ and $3l^2 + 5m^2 - 11n^2 = 0$,then the angle between the two lines is

If the direction ratios of two lines are proportional to $(2, 3, -6)$ and $(3, -4, 5)$,then the acute angle between them is

The angle between the lines whose direction ratios satisfy the equations $l+m+n=0$ and $l^2=m^2+n^2$ is

$A$ line makes a $45^{\circ}$ angle with the positive $X$-axis and makes equal angles with the positive $Y$-axis and $Z$-axis respectively. The sum of the three angles which the line makes with the positive $X$-axis,$Y$-axis,and $Z$-axis is: (in $^{\circ}$)