**Diagram Interpretation Workbook-1**

*Parallel lines : *

**Parallel lines** are two or more **lines** that are always the same distance apart and never intersect each other. In order for two **lines** to be **parallel**, they must be drawn in the same plane, a perfectly flat surface like a wall or sheet of paper. If a line l is parallel to other line m and line m is parallel to line n then line l is also parallel to line l.

**parallel lines** will **always** be **straight lines** that go on indefinitely.

**Perpendicular line :**

Perpendicular lines are lines that intersect at right angles. OR

A **line** meeting another at a right angle, or 90° is said to be **perpendicular** to it .

If two lines are perpendicular to each other and a third line is perpendicular to eany one of them then this third line will be parallel to the other line;

**l **^ **m and m **^ **n then l is parallel to n. **

*Congruent lines : *

**Congruent** segments are simply **line** segments which are equal in length. By defination **Congruent** means equal.

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