The obtuse angle between the lines $y = -2$ and $y = x + 2$ is .....$^o$

If the equation of a line having a slope $m$ $(m \in \mathbb{Z})$,passing through $(1, 1)$ and making an angle of $\tan^{-1}\left(\frac{5}{7}\right)$ with the line $x + y - 3 = 0$ is $ax + y + c = 0$,then $ac =$

The angle between the straight lines $3x + 4y + 9 = 0$ and $x - 7y - 22 = 0$ is

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

The angle between the lines $x - \sqrt{3}y + 5 = 0$ and the $y$-axis is ....$^o$

The acute angle between two straight lines passing through the point $M(-6, -8)$ and the points in which the line segment $2x + y + 10 = 0$ enclosed between the coordinate axes is divided in the ratio $1 : 2 : 2$ in the direction from the point of its intersection with the $x$-axis to the point of intersection with the $y$-axis is: