Perpendicular and Parallel


It just means at right angles (90°) to.

The red line is perpendicular to the blue line:

Perpendicular Examples

Here also:

Perpendicular Examples

(The little box drawn in the corner, means "at right angles", so we didn't really need to also show that it was 90°, but we just wanted to!)

Try for yourself:



Lines are parallel if they are always the same distance apart (called "equidistant"), and will never meet. (They also point in the same direction). Just remember:

Always the same distance apart and never touching.

The red line and blue line are parallel in both these examples:

Parallel Example 1
Example 1
Parallel Example 2
Example 2

Try it yourself:


Perpendicular to Parallel

Question: What is the difference between perpendicular and parallel?
Answer: 90 degrees (a right angle)

That's right, when we rotate a perpendicular line by 90° it becomes parallel (but not if it touches!)

Perpendicular ...
Rotate 90 Degrees
rotate one line 90°
... Parallel

Likewise, parallel lines become perpendicular when one line is rotated 90°.

Parallel Curves

Curves can also be parallel when they keep the same distance apart (called "equidistant"), like railroad tracks.

The red curve is parallel to the blue curve in both these cases:

Parallel Curves Example 1
Parallel Curves Example 1

Parallel Surfaces

Surfaces can also be parallel, like this:

Parallel Surfaces

plane perpendicular

Lines and Planes

Advanced Topic: You can also learn about Parallel and Perpendicular Lines and Planes


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