Parallel and Perpendicular Lines

Front

What are parallel lines?

Back

Parallel lines are lines in a plane that never meet or intersect. 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 two lines have the same slope, what can we say about them?

Back

If two lines have the same slope, they are parallel.

Front

What is the slope of a line parallel to a line with slope 3?

Back

The slope of a line parallel to a line with slope 3 is also 3.

Front

What is the slope of a line perpendicular to a line with slope 2?

Back

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

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 neither parallel nor perpendicular to a line with slope 1?

Back

Any slope that is not equal to 1 or -1 is neither parallel nor perpendicular.

Front

If line A has a slope of 5 and line B has a slope of -1/5, what can we say about the lines?

Back

Line A and line B are perpendicular.

Front

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

Back

The slopes of two parallel lines are equal.