Parallel and Perpendicular Lines

Front

What are perpendicular lines?

Back

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

Front

What is the relationship between the slopes of two perpendicular lines?

Back

The slopes of two perpendicular lines are opposite reciprocals of each other.

Front

What are parallel lines?

Back

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

Front

What is the relationship between the slopes of two parallel lines?

Back

The slopes of two parallel lines are equal.

Front

If a line has a slope of 2, what is the slope of a line that is perpendicular to it?

Back

The slope of a line that is perpendicular to a line with a slope of 2 is -1/2.

Front

How can you identify parallel lines in a graph?

Back

Parallel lines in a graph will have the same slope and will never intersect.

Front

How can you identify perpendicular lines in a graph?

Back

Perpendicular lines in a graph will intersect at a right angle (90 degrees).

Front

What is the slope of a line that is horizontal?

Back

The slope of a horizontal line is 0.

Front

What is the slope of a line that is vertical?

Back

The slope of a vertical line is undefined.

Front

If two lines have slopes of 3 and -1/3, what can you say about their relationship?

Back

The lines are perpendicular because their slopes are opposite reciprocals.