If a line makes angles $90^{\circ}$,$135^{\circ}$,and $45^{\circ}$ with the positive directions of $X$,$Y$,and $Z$-axes respectively,then its direction cosines are:

Direction cosines of the line $\frac{x+2}{2} = \frac{2y-5}{3}, z = -1$ are $.......$

Consider the following statements:
Assertion $(A)$: The direction ratios of a line $L_1$ are $2, 5, 7$ and the direction ratios of another line $L_2$ are $\frac{4}{\sqrt{19}}, \frac{10}{\sqrt{19}}, \frac{14}{\sqrt{19}}$. Then the lines $L_1, L_2$ are parallel.
Reason $(R)$: If the direction ratios of a line $L_1$ are $a_1, b_1, c_1$, the direction ratios of a line $L_2$ are $a_2, b_2, c_2$ and $a_1 a_2 + b_1 b_2 + c_1 c_2 = 0$, then the lines $L_1, L_2$ are parallel. Which one of the following is true?

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

If $l_1, m_1, n_1$ and $l_2, m_2, n_2$ are direction cosines of $OA$ and $OB$ such that $\angle AOB = \theta$,where $O$ is the origin,then the direction cosines of the internal angular bisector of $\angle AOB$ are

The direction cosines of a line which makes equal angles with the coordinate axes are . . . . . .