If $3x + 4y - 5 = 0$ and $4x + ky - 8 = 0$ are two parallel lines,find the value of $k$.

Two lines pass through the point $(2,3)$ and intersect each other at an angle of $60^{\circ}$. If the slope of one line is $2$,find the equations of the other line.

$A$ value of $k$ such that the straight lines $y-3kx+4=0$ and $(2k-1)x-(8k-1)y-6=0$ are perpendicular is

Statement $(A)$ : The line $2x + y + 6 = 0$ is perpendicular to the line $x - 2y + 5 = 0$ and the second line passes through $(1, 3)$.
Reason $(R)$ : The product of the slopes of perpendicular lines is $-1$.

If the angle between the lines is $\frac{\pi}{4}$ and the slope of one of the lines is $\frac{1}{2}$,then the slope of the other line is

The angle between the line $x+y=3$ and the line joining the points $(1,1)$ and $(-3,4)$ is