Find the octants in which the points $(-3, 1, 2)$ and $(-3, 1, -2)$ lie.

The perpendicular distance of the point $P(6, 7, 8)$ from the $XY$-plane is:

What are the direction cosines of the line joining the points $(4, 3, -5)$ and $(-2, 1, -8)$?

If a line makes angles $90^{\circ}, 60^{\circ}$ and $\theta$ with $x, y$ and $z$ axes respectively,where $\theta$ is acute,then the value of $\theta$ is

The direction cosines of three lines passing through the origin are $(l_1, m_1, n_1)$,$(l_2, m_2, n_2)$,and $(l_3, m_3, n_3)$. The lines will be coplanar if

Each of the angles $\beta$ and $\gamma$ that a given line makes with the positive $y-$ and $z-$axes,respectively,is half of the angle that this line makes with the positive $x-$axis. Then the sum of all possible values of the angle $\beta$ is