Sometimes it is hard to tell if two lines are parallel, skew or intersecting. The best way to find out is by determining the distance between them and then use a ruler to measure their angle. -First, measure the distance between lines l and l’. If this is less than or equal to their slope then they are parallel.
Next, make an angle with a ruler at line L (the point where you started measuring) and line L’(the end of the measurement). The two angles should be 45 degrees apart for them to intersect. If one of these angles is greater than 90 degrees it means that the lines are skew.
Finally, if both distances measured were greater than or equal to their slopes then there is no way to tell whether the lines are skewed unless you know more information about them like length measurements for example. However in most cases when this happens we can use linear algebra.