Subject: Geometry

# Line Types

### Intersecting lines

Lines are said to be intersecting if they meet at a common point.

**\overleftrightarrow{AB} and \overleftrightarrow{CD} intersects at point (1, -1)**

### Parallel Lines

Lines are said to be parallel if it does not intersect or meet at a certain point on the same plane *(co-planar)*. The relationship is symbolized with " || " between the line names. Suppose, \overleftrightarrow{AB} is parallel to \overleftrightarrow{CD} .
It will be written as \overleftrightarrow{AB} || \overleftrightarrow{CD} .

**\overleftrightarrow{AB} || \overleftrightarrow{CD} .**

### Perpendicular Lines

Lines are said to be perpendicular, if a line intersects another line forming a right angle. The relationship is symbolized with " ⊥ " between the line names. Suppose \overleftrightarrow{AB} is perpendicular to line \overleftrightarrow{CD} , it will be written as \overleftrightarrow{AB} ⊥ \overleftrightarrow{CD}

**\overleftrightarrow{AB} ⊥ \overleftrightarrow{CD} .**

### Transversal Lines

A line is said to be transversal if it goes across two lines which are usually parallel. If it crosses parallel lines it is called ''perpendicular transversal."

**perpendicular transversal**

**non-parallel case**