Parallel and Perpendicular Lines

Front

What are parallel lines?

Back

Parallel lines are lines in a plane that never meet. 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 perpendicular lines are negative reciprocals of each other.

Front

If the slope of a line is m, what is the slope of a line parallel to it?

Back

The slope of a line parallel to it is also m.

Front

If the slope of a line is m, what is the slope of a line perpendicular to it?

Back

The slope of a line perpendicular to it is -1/m.

Front

What is the slope of a line with a slope of 4?

Back

The slope of a line with a slope of 4 is 4.

Front

Given the slopes of two lines, how can you determine if they are parallel?

Back

If the slopes of the two lines are equal, then the lines are parallel.

Front

Given the slopes of two lines, how can you determine if they are perpendicular?

Back

If the product of the slopes of the two lines is -1, then the lines are perpendicular.

Front

What is the slope of a line that is perpendicular to a line with a slope of 5/11?

Back

The slope of a line that is perpendicular to a line with a slope of 5/11 is -11/5.

Front

What is the slope of a line that is parallel to a line with a slope of 9/10?

Back

The slope of a line that is parallel to a line with a slope of 9/10 is 9/10.

Front

If two lines have slopes of 8/9 and 8/9, what can you say about the lines?

Back

The lines are parallel.