Parallel lines are denoted by the parallel symbol placed betwen the notation for two lines. For example, the expression means that the line is parallel with the line .
We can draw the two parallel lines like this:
The arrows on the lines also indicates that the two lines are parallel to each other.
A line is written as two letter with a line overtop, where the letters represent the end points of the line.
The symbol for two perpendicular lines is a horizontal line with another line drawn perpendicular to it.