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**Parallel**&

**perpendicular**lines.

**Parallel**lines are lines in a plane that are always the

**same**distance apart.

**Parallel**lines never intersect.

**Perpendicular**lines are lines that intersect at a right (90 degrees) angle.

Similarly, you may ask, what is the difference between perpendicular and parallel?

Two lines are said to be **parallel** when they are equidistant from each other and will never intersect or touch. In simple terms, the slope of two **parallel** lines is equal. Slope of **perpendicular** lines, on the other hand, are negative reciprocals of each other meaning the lines cross each other at right angle.

**Perpendicular**lines can face any

**direction**. They can be crossways, up and down, or

**side**-to-

**side**on the page. They do NOT need to be standing straight up from the bottom or

**side**of the page. They just have to be 90° to each other.

Similarly, you may ask, are train tracks parallel or perpendicular?

The ties of a **railroad track** are **perpendicular** to the **rails** and of the same length. This common length is the distance between the **rails**. (If **parallel** lines exist, then **railroad tracks** in space can go on forever.)

**Perpendicular lines** intersect at right angles to one another. To **figure out if** two equations are **perpendicular**, take a look at their slopes. The slopes of **perpendicular lines** are opposite reciprocals of each other. Their product is -1!