`m = -7/9` find the inclination 'theta' (in radians and degrees) of the line with slope m.

You need to use the following formula to evaluate the inclination angle theta, such that:

`tan theta = m`

Replacing-`7/9` for m,  yields:

`tan theta = -7/9 => theta = tan^(-1)(-7/9) => theta = -tan^(-1) (7/9)`

`theta = -37^o 50' 49''`

The answer in radians can be calculated such that:

`theta = (-37^o 50' 49''*pi)/(180^o)`

`theta =- 0.660` radians

Hence, evaluating the angle theta in degrees and radians yields `theta = - -37^o 50' 49''` or` theta` = - 0.660 radians.