l1, l2, l3, and l2 can be used to determine whether two lines intersect, intersect, or are parallel. By determining the slope of the lines, it can also be used to determine whether two or more lines intersect, and therefore whether they are perpendicular.
l1 is a straight line and can be used to determine whether two lines are perpendicular, if they intersect. If the two lines are parallel, you have a right angle and this indicates that they do intersect. If you have a right angle, either the two lines are actually straight, in which case this indicates a skew or an intersection. If the lines do not intersect, or if they intersect in only one direction, but not in both directions, then this is an angle.
L1 can be used to determine if one line slopes downward or upward, or whether the lines intersect in a perpendicular or horizontal direction, or whether the two lines intersect in a vertical direction versus in a horizontal direction. l2 is the hypotenuse of a right triangle, and can be used to determine whether two lines follow a straight line, skew, or intersect. In order to determine if the lines intersect, you can make a right angle determination.
Using the angles for a slope, you can find out how to determine if two lines intersect, or if they cross. This is possible if the two lines are on the common side of the angle, or if both lines are on the common side of the angle, and one of the lines is at the other end of the angle. Or, if the angles are not on the same side of the figure, you can determine which of the two angles makes the line a vertical line.
Lines are lines if they bend, cross, or turn. The definition of a straight line is a line that lies flat or parallel to another line. How to determine where two straight lines intersect: For all lines not intersecting in your drawings, you will need to know where the lines begin and the end of one line and compare them. For all lines intersecting, you will need to compare them and see which of the two ends the line crosses.