Parallel and Perpendicular Lines

Front

What are parallel lines?

Back

Parallel lines are lines in a plane that never meet and are always the same distance apart. They have the same slope.

Front

What are perpendicular lines?

Back

Perpendicular lines are lines that intersect at a right angle (90 degrees). The slopes of two perpendicular lines are negative reciprocals of each other.

Front

How can you determine if two lines are parallel using their slopes?

Back

Two lines are parallel if their slopes are equal.

Front

How can you determine if two lines are perpendicular using their slopes?

Back

Two lines are perpendicular if the product of their slopes is -1.

Front

What does it mean if two lines are neither parallel nor perpendicular?

Back

If two lines are neither parallel nor perpendicular, they intersect at an angle that is not 90 degrees and their slopes are neither equal nor negative reciprocals.

Front

If the slope of line #1 is 3 and the slope of line #2 is 3, what can you conclude about the lines?

Back

The lines are parallel.

Front

If the slope of line #1 is 2 and the slope of line #2 is -1/2, what can you conclude about the lines?

Back

The lines are perpendicular.

Front

What is the slope of a horizontal line?

Back

The slope of a horizontal line is 0.

Front

What is the slope of a vertical line?

Back

The slope of a vertical line is undefined.

Front

If two lines have slopes of 5 and -5, are they parallel, perpendicular, or neither?

Back

They are neither parallel nor perpendicular.